Retention arithmetic that quietly drifts

Retention looks simple on page one of a contract and complicated by month twelve. Percentages change after practical completion, early releases are granted without reversing the ledger, and final accounts inherit a balance that nobody has rebuilt from scratch.

Where drift begins

Common sources we see in financial audit of vendor payment applications:

• Applying the wrong retention rate after a milestone date
• Releasing retention on one package while the ledger still shows it held
• Carrying forward a rounded figure that no longer matches the claim history
• Ignoring a defects notice that should have paused a scheduled release

What a close-out check does

A retention and final account check rebuilds the held and released amounts from the payment history, then compares the result to the contract’s release conditions. The output is not a theory—it is a reconciliation you can attach to the final transfer request.

Practical habit

Once a quarter, ask for a retention roll-forward that lists each vendor’s held balance, releases in the period, and the contractual reason for each movement. When that schedule is missing, expect exceptions at close-out.