CloudLink: illustrative cost investigation worksheet
Version 1 | 2026-11-03 | Organization: CloudLink
Article: https://cloudlink.us/blog/cloud-cost-anomaly-detection
Data: CO-685-finops-spend-v1.csv (all four amounts and dates are synthetic)

REPRODUCE WITHOUT AN ACCOUNT
Open the CSV in a text editor or spreadsheet. All rows describe complete,
equal-length UTC days for one invented workload, USD, same cost definition.
Baseline = (100 + 102 + 101) / 3 = 101 USD/day.
Fourth day = 141 USD. Difference = 141 - 101 = 40 USD.
Percentage change = 40 / 101 * 100 = 39.603960...%, rounded to39.60%.
Illustrative review gate: difference >20USD AND percentage >20%.
Both conditions pass. Outcome: investigate, with no automatic resource change.
For a zero baseline, percentage is undefined: record new spend for manual review.

LIMITS
This is arithmetic, not the AWS machine-learning detection algorithm or a forecast.
No cloud APIs, credentials, customer data, real alert, root-cause proof, waste,
savings, service delivery result or performance benchmark is provided.
A three-day baseline is deliberately small; it cannot represent seasonality.
Real comparisons must normalize currency, metric, scope, day length/timezone,
completeness, discounts, refunds, credits, late billing, traffic and scheduled jobs.
Do not treat a positive difference as recoverable savings or permission to act.

FILL IN FOR YOUR OWN REVIEW (do not include credentials or customer personal data)
Comparison scope / metric / currency / timezone:
Baseline and comparison windows / completeness checks:
Billing source version / observed-at timestamp:
Material usage, deployment, schedule or billing changes:
Workload and billing owner:
Evidence supporting a cause / remaining uncertainty:
Decision: investigate further, accept growth, or propose a reversible change:
Named approver and approval reference (before any change):
Proposed change / reliability check / rollback:
Complete follow-up window / result / closure evidence:

REFERENCE AND HANDOFF
Provider documentation (read 2026-11-03):
https://docs.aws.amazon.com/cost-management/latest/userguide/manage-ad.html
AWS describes its own model and billing-data limits; it does not supply this CSV.
For recurring allocation and review ownership, discuss the scope with CloudLink:
https://cloudlink.us/solutions/finops