Analysis Sponsor Readout
seatlark-cost-3-readout.pdf
The baseline, the savings ranked, the decisions the sponsor needs to make, and what the next four weeks will put in place.
Download PDF of Analysis Sponsor ReadoutSample case study · AWS cost analysis & optimization
Six weeks with Seatlark, Inc., a fictional ticket exchange eleven months into a move out of its colocation data center, on an AWS bill of $51,660 a month. The Analysis found $246,839 a year. Seatlark’s engineers put $155,076 of it in place, and their Cost and Usage Report measured $148,967.This is the case for a bill of about $50,000 a month in the middle of a migration. At your size, the gate is three times the fee, $105,000 a year, 16.9% of Seatlark’s bill, and Seatlark cleared it 4.35 times. It shows the method, not a typical result.
Seatlark, Inc. is a fictional company: every account, figure, and person on this page is simulated. The AWS prices are real list prices, retrieved October 13 and 16, 2026.

Seatlark, Inc. does not exist. We built it to show what this engagement produces at the bottom of its range: an AWS organization of 16 accounts and about $50,000 a month, eleven months into a two-year move out of a colocation data center, simulated resource by resource and priced at AWS list prices, with nine Seatlark people who make the decisions real owners make. Then we ran the six-week Optimization against it, week by week, and wrote the reports.
The eight reports are the real deliverables, written the way we write them for a client, and they agree with each other to the dollar because every figure comes from one deterministic simulation. The engagement is dated May 11 to June 18, 2026, and priced at October 2026 list prices. Our clients’ bills stay confidential, so this is how we can show you every page.
Seatlark’s AWS bill went from $3,900 a month in May 2025 to $49,600 in April 2026 as the migration landed, 12.7 times in eleven months, and everyone expected that. What nobody could say was whether $49,600 was the right number for what had moved, or what the bill would be when the colocation lease ends. The migration business case the board approved assumes $1.5 million a year at the end, and the CTO wanted an answer before the last and largest waves moved.
Renee Castellano signed the six-week Optimization: the two-week Analysis first, then four weeks of putting the savings in place through Seatlark’s own pull requests and change tickets, and the same bill read again at the end. Owen Pradhan, who runs the migration program, led it day to day, and Lydia Brandt, the vice president of finance, made every purchase decision.
Each week ended with a report, and every report is below. The dates in each week are the engagement’s own, and a production freeze from June 4 to 14 shaped weeks four to six.
The read-only role went into all 16 accounts on Tuesday, and twelve months of the Cost and Usage Report came with it, tied to each month’s invoice before it was used. The bill had risen in every month of the ramp, from $3,900 to $51,660 a month.
It also showed what a lift-and-shift estate looks like: all 67 EC2 instances On-Demand, with no Savings Plan or reservation because finance had deferred every commitment until the migration completes, 42 of them under 10% CPU, including all 14 of the replication servers the migration tool left running, and $12,280 a month, 24% of the bill, with no owning team tag. Every page view on the exchange still calls the orders database in the colo across Direct Connect.
The calendar. Kickoff on Monday, May 11; read-only access on Tuesday, the inventory on Wednesday, the invoice tie-out on Thursday, and the baseline report on Friday, May 15.
In the room. Six sessions: the kickoff, a finance session with Lydia Brandt, the architecture and migration-tooling walkthroughs, and two office hours.
Every saving was priced in a fixed order, so nothing was counted twice: 30 changes on 244 resources, $246,839 a year, 39.8% of the bill, for a one-time cost of $3,117. That is 2.35 times the gate, so the engagement continued. If every change landed, the bill would fall by $20,570 a month, from $51,660 to $31,090.
The readout, on Friday, May 22, gave a planning range, not a promise: $136,161 to $156,116 a year in place by June 18, against the $105,000 gate. It also answered the board’s question. At colo exit the bill reaches $125,300 a month, $1.5 million a year, if nothing is done, which is Seatlark’s own plan, and about $107,717 a month with the approved roadmap landed.
Then each owner went through the roadmap, finding by finding. They approved 27 of the 30 changes, $210,993 a year at their estimates, and declined three.
Decisions at the readout. Seven: the roadmap, finding by finding; a production freeze from June 4 to 14; the commitment, by June 3; the second Direct Connect port; a load test before two production resizes; the event renditions; and a notice period for the partner database.
In the room. Six sessions: the on-sale calendar and freeze windows, a search and catalog walkthrough, two office hours, the savings review with the owners, and the sponsor readout.
14 changes in a four-day week, estimated at $98,760 a year across 159 resources: test-cutover volumes and left-over migration servers deleted, non-production schedules, gp2 volumes moved to gp3, S3 gateway endpoints for the 13 TB a month of S3 traffic that was crossing NAT gateways, one NAT gateway instead of three in non-production, log retention, and 28 TB of migration backups moved to Deep Archive. Nine went in as pull requests and five as change tickets.
Not everything went in. The three changes declined at the readout stayed out, and their reasons are below.
The calendar. Memorial Day was Monday, May 25, so the week had four working days. The freeze plan agreed at the readout was already in force: every production change was scheduled for June 2 to 3 or after June 14.
In the room. Seven sessions: two change reviews, two pairing sessions on the waste runbook and the non-production schedule, two office hours, and a sponsor check-in.
6 changes worth $56,316 a year, which brought the total in place to 20 changes and $155,076 a year at their estimates, 1.48 times the gate before anything was measured. Production rightsizing went in on June 2, ahead of the freeze: the marketplace API tier and the partner APIs, six hosts each, moved from m5.2xlarge to m5.xlarge, one host at a time behind the load balancer. The on-sale on Friday, June 5 was the live test, and the API tier peaked at 61% CPU on the smaller size, three points above the 58% predicted from April and one point over the 60% ceiling the Analysis had set. By that rule it was over the line, not a pass, so the tier stayed on the smaller size with an alarm at 75% CPU, and the on-sale on June 10 decided whether it stayed: the API tier peaked at 57%, and the partner APIs ran their busiest feed at 41%, against the 42% projected. The web tier stayed on its larger size, because halving it would have put its April peak at 82%.
On Wednesday, June 3, Lydia Brandt approved the commitment: a one-year No Upfront Compute Savings Plan at $5.00 an hour, bought by Seatlark’s finance team in the management account that afternoon. It covers 58.6% of the always-on compute floor and saves $15,950 a year, 26.7% off what it covers. She declined a three-year plan and an all-upfront payment for now, because the team does not know what checkout will run on in a year.
The calendar. Rightsizing on Tuesday, June 2; the commitment on Wednesday, June 3; and the last change of the engagement that same day, before the freeze began on Thursday, June 4.
In the room. Eight sessions: two change reviews, two pairing sessions on the ticket-scan lifecycle rule and the API tier rolling update, the commitment decision meeting, two office hours, and a sponsor check-in.
From June 4 to June 14, around the biggest on-sale of the summer, nothing that changes what production runs went in. What did go in was everything that only watches or only applies to what is new, so the savings stay: ten guardrails, among them budgets and anomaly monitors in all 16 accounts, a tag policy, a Config rule and a service control policy against new gp2 and io1 volumes, Instance Scheduler as the non-production default, log retention in the account baseline, a VPC template with gateway endpoints, and two rules in the wave runbook for the waves still to come.
One change came out. Diego Saldana, the director of partner engineering, found that white-label partners hotlink the image renditions for past events, so deleting 11 TB of them would have broken partner pages, and he reversed an approval he had given at the readout. The statement of work counts a change approved at the readout and declined later at its estimate, $3,109 a year, so the guarantee cannot be met by approving a change and never making it.
The calendar. No production change from Thursday, June 4 to Sunday, June 14. The tag policy reaches production on June 15 and the service control policy on June 23, after the production search volumes are changed.
In the room. Eight sessions: two change reviews, two office hours, a pairing session on the guardrails, the review of the rendition reversal, a working session on the wave runbook, and a sponsor check-in.
Every change was measured on the Cost and Usage Report the same way: public On-Demand cost for the changed resources, seven days before against seven days after, so that the Savings Plan, bought on June 3, is never counted twice; the plan itself is measured on its own, by its ARN. 20 changes measured $148,967 a year, 96.1% of the $155,076 estimated for them, and every miss is published at its measured value. Eight measured at their estimate and nine came within 1% to 6% of it. Three came in at 88% to 91%: debug logging that two services kept on through the freeze (their deploys were queued behind the release train), snapshots that share blocks so that deleting one freed less than the estimate used, and on-sale rehearsals that kept the performance-test fleet running 140 hours in June instead of the 96 planned.
A whole-bill check agreed. Business Support+ bills monthly and has no daily line in the Cost and Usage Report, so it stays out of the check. Once wave 6’s $2,600 a month is accounted for, the fall in the daily bill left $5,764 a year unexplained, 4.9% of the expected fall and inside the noise of two seven-day averages. The handover gave every remaining line of the roadmap an owner and a date, and set the first monthly cost review for July 14. The second invoice, $17,500, was issued with the measurement report, so Seatlark paid $35,000 in total.
The calendar. Measurement on Wednesday, June 17, from the Cost and Usage Report through June 15; the closing readout on Thursday, June 18, because Juneteenth is a company holiday.
In the room. Five sessions: office hours, the handover workshop, a pairing session on the measurement, the closing readout, and a rehearsal of the monthly cost review.
Half the fee rode on one number: annualized savings in place at week six, measured on Seatlark’s own Cost and Usage Report, of at least three times the fee. Each step from estimate to measurement is in the reports.
a year across 30 changes on 244 resources, 39.8% of the bill, priced in week two.
a year at estimate, in 20 changes their owners approved and Seatlark’s engineers applied.
a year across those 20 changes: 24.0% of the bill and 96.1% of their estimate, every miss included.
Counted toward the gate: $152,076 a year, the measured $148,967 plus $3,109 for the one change approved at the readout and declined later. That is 4.35 times the $35,000 fee, against a gate of three times. Measured alone it is 4.26 times, and net of the $3,117 one-time cost of the changes, $148,959 a year, it is still 4.26 times. The 17 high-confidence changes alone, measured at just 90% of their estimates, would still have cleared it, at $120,951. Seatlark paid $35,000 in total, because the Analysis is the Optimization’s first two weeks. The measured savings repay it in 2.8 months and net $113,967 in the first year. The counted figure decides the gate only.
Still to come: $52,808 a year across six changes that are approved and scheduled, each with an owner and a date, and $35,846 a year across three that were declined and can be reopened. Why it cleared: Seatlark was a lift-and-shift estate with no commitments, which is the easiest bill there is to cut. A bill that has already been optimized, or already carries commitments, finds less, and the Analysis says so at the week-two readout, where the engagement can stop.
Want this gate on your own organization?
Book a call about the OptimizationA guarantee that counted only the changes owners agreed to would be easy to meet, so the reports show every call, with the owner who made it and the reason. Ten changes did not reach the bill by week six, and one purchase did.
Seatlark had no Savings Plans or reservations when the engagement began. Finance decided on June 3, and Seatlark’s finance team made the purchase. Vantalect buys nothing.
Sized to cover 58.6% of the always-on compute floor, below it on purpose: a Savings Plan can be returned only within seven days of purchase, in the same calendar month, and after that it cannot be canceled, so it has to stay fully used after every deferred resize. A three-year plan would take about 49% off instead of 26.7%, and it waits for colo exit, when the estate is known.
Decided. Wednesday, June 3, by Lydia Brandt with Renee Castellano.
An owner said no, with a reason, and the decision is on the record. Each can be reopened.
Traffic peaks at 1.1 Gbps and runs about 380 Mbps at the 95th percentile, so a 1 Gbps failover port would cap below the peak unless the nightly backup copy is shaped, and the July orders-database cutover uses the second port as its failover path. Hosted 2 or 5 Gbps connections are priced by the AWS Partner, not on the Price List, so they are not priced here. The ports are revisited at colo exit.
Compute Optimizer never saw an on-sale, so the owner asked for a load test first. It is rescheduled as a performance-test exercise after the freeze.
Staging runs the overnight on-sale rehearsals and the partner acceptance tests in other time zones, and the schedule would interrupt both.
Each is approved, owned, and dated. None was in place by June 18, so none counts toward the gate. One waited on the peak-season freeze, one on a load test and a partner’s notice period, and one on an application change.
The change waits for the production freeze to end and for the biggest on-sale of the summer. The owner will not touch the search cluster in the week before it.
Target. June 22.
Seatlark Connect’s partner contracts require ten business days’ notice of a maintenance window. The change halves the database’s memory, so a load test against a restored copy comes first, and the notice goes out when it passes, by June 11, for the window on June 27. A notice sent at the readout would have put the earliest window on June 8, inside the freeze.
Target. June 27.
An application change: cache the order-status and held-inventory calls to the orders database in the colo, and read within the Availability Zone. It is approved for the third-quarter sprint.
Target. August 14.
A load test that replays an on-sale, then the July maintenance window.
Target. July 9.
The July container replatform, which moves the marketplace to arm64 images.
Target. July 23.
An arm64 build of the partner APIs, validated in staging.
Target. July 10.
The statement of work counts a change approved at the readout and declined later at its estimate, so this one is in the gate math and was never made.
White-label partners hotlink rendition URLs on archived event pages, and deleting them would break partner pages. The owner reversed his approval in week five.
Seatlark’s own plan adds $71,000 a month over the five waves that have not moved, from $54,300 after wave 6 to $125,300 at colo exit, $1.5 million a year. That plan sizes each wave the way the first six were sized, from the colocation hardware.
The Optimization leaves behind a wave runbook and the week-five guardrails, so the waves still to come are sized from 30 days of actual use, scheduled in non-production, built from the VPC template, and cleaned up after cutover. The range is what that is worth at the end-state run rate: 12% to 20% of the $71,000 a month still to be added.
It is a model, not a measurement. Nothing in it has happened, none of it is on the bill, and none of it counts toward the gate or was used to clear it. If Seatlark’s real end state is larger than its plan, the range grows by 1.6 to 2.1 times.
One more avoidance item sits beside the forecast. RDS for MySQL 8.0 standard support ends on July 31, 2026, and every 8.0 instance left after that bills Extended Support from August 1, at $0.10 a vCPU-hour. Once D-1 and D-2 are done the two partner databases would cost $730 a month, or $1,314 if D-2 slips, and moving them to MySQL 8.4 in D-2’s window on June 27 avoids it. It is cost avoidance priced from the Price List, it is separate from the range, and it is not counted toward the gate.
At the end-state run rate, $8,520 to $14,200 a month. A planning range on the migration still to come: not measured, not counted toward the gate, and not a saving on the bill.
Cost avoidance is a forecast of a bill that has not happened, so it sits apart from the gate on purpose. The gate counts savings on the bill, measured on Seatlark’s own Cost and Usage Report, and nothing else: $152,076 a year, with none of this in it.
The engagement ran in a Pavilion workspace, created from the Optimization’s template with every week, session, deliverable, and obligation already in place, on Seatlark’s calendar and in its time zone. Ten people joined it: the sponsor, finance, the platform, marketplace, search, partner, fulfillment, and data owners, and Charles.
After each session the transcript came into the workspace, and an agent drafted the summary, the decisions taken, the action items, and a digest for the people who were not in the room, each claim citing the part of the transcript it came from. Charles reviewed every draft before Seatlark saw it. Five pairing sessions were not recorded, so each of those got consultant notes instead.
Every report was published there as an immutable, hashed version, and Renee Castellano accepted each one against that version. The deliverables were checked off against that evidence, and the measurement panel kept the baseline, the weekly estimates, and the closing measurement side by side, so an estimate and a measurement were never mistaken for each other.

When the production search volumes waited for the freeze and the biggest on-sale of the summer, the decision kept its condition, its owner, and a task dated June 22, so anyone reading the roadmap later finds the reason next to the line.
Seatlark Connect’s contracts require ten business days’ notice of a maintenance window, so the partner database resize carries a load test against a restored copy first, then the date the notice must go out, June 11, and the window on June 27, after the freeze.
The Savings Plan was approved by Lydia Brandt and bought by Seatlark’s finance team. Vantalect holds no write access and buys nothing, and the record shows which side did what.
Diego Saldana’s reversal of the rendition deletion is recorded as approved and then declined, with his reason, so when the sponsor accepted the measurement, the reason for the $3,109 line was a click away.
The engagement’s last tasks hand the roadmap to Seatlark: every remaining change with an owner and a date, and the first monthly cost review on July 14. Then the workspace closed.
Nine PDFs and 194 pages. Start with the readout; the reading guide shows how the rest fit together. Then read the weeks in order and you have the engagement the way Seatlark’s sponsor did. Each one is tagged for screen readers, and each says on its cover that Seatlark is fictional.
Written for the sponsor, and the one to read if you read nothing else: the baseline, the savings ranked, the seven decisions the sponsor needs to make, and what the next four weeks will put in place.
seatlark-cost-3-readout.pdf
The baseline, the savings ranked, the decisions the sponsor needs to make, and what the next four weeks will put in place.
Download PDF of Analysis Sponsor ReadoutThe full analysis behind the readout: the waste register, the rightsizing plan, the commitment plan, and the ranked savings roadmap, with the prescriptive change for each.
seatlark-cost-2-analysis.pdf
Twenty-nine findings priced from the AWS price list and ranked, the waste register, the rightsizing plan, the commitment plan, and the prescriptive change for each.
Download PDF of Cost Analysis and Savings RoadmapThe reading guide first, then what each week delivered, in order.
seatlark-0-guide.pdf
Who Seatlark, Inc. is, what each of the eight sample cost reports delivers, what the engagement found and fixed halfway through a migration to AWS, and what is real and what is simulated.
Download PDF of Sample Engagement Reportsseatlark-cost-1-baseline.pdf
Twelve months of Seatlark’s AWS spend as a migration ramp, the May run rate by account, service, environment, and team, the resource inventory, and the migration trajectory with no action.
Download PDF of Spend Baseline and Inventoryseatlark-cost-4-quick-wins.pdf
Waste removed, non-production schedules, storage, logging, network endpoints, and non-production databases, change by change, with what was declined and why.
Download PDF of Quick Wins Appliedseatlark-cost-5-rightsizing-commitments.pdf
Production rightsizing before the freeze, the ticket-scan lifecycle, and the commitment decision finance approved.
Download PDF of Rightsizing and Commitmentsseatlark-cost-6-architecture-guardrails.pdf
The guardrails, the wave runbook, and the cost-avoidance model for the remaining migration waves, built during the production freeze.
Download PDF of Architecture Changes and Guardrailsseatlark-cost-7-measurement.pdf
Every change measured on Seatlark’s Cost and Usage Report, annualized, and the guarantee’s gate.
Download PDF of Week-Six Savings Measurementseatlark-cost-8-handover.pdf
The remaining roadmap with owners and dates, the commitment ladder, the monthly cost review, and the KPIs Seatlark runs from here.
Download PDF of Handover Playbook and Monthly Cost ReviewThe same six weeks and the same gate, on your own Cost and Usage Report, in the middle of a migration or not.

The Analysis and the Optimization: the baseline, the waste register, and the roadmap in two weeks, then the savings put in place and measured, with half the fee riding on the result.
Read the engagement
A fictional robot maker with 48 accounts and a $55.7 million bill: $23.5 million a year identified, and $9.4 million measured on its own Cost and Usage Report.
Read the case studyTell us roughly what the bill is, where the migration stands, and what prompted the question. You will hear back from Charles within one business day, and the first call is fifteen minutes.
AWS, Amazon Web Services, AWS Graviton, and the AWS service names are trademarks of Amazon.com, Inc. or its affiliates. Vantalect is not affiliated with or endorsed by Amazon. Seatlark, Inc. and every person named on this page are fictional.