Confirm the delivery list first
Your quote should identify the program and version, expected files, included dependencies and any agreed modifications. A program repair and full source delivery are separate outputs. Keep the written scope alongside the reference file.
Compare the same conditions
Use the same terminal environment, symbol, timeframe, inputs and relevant dates. Compare displays, alerts or EA orders according to the agreed scope. Keep screenshots and logs with timestamps when a discrepancy occurs. One matching image does not cover every possible input combination.
Make approval explicit
Report either approval or reproducible differences, then confirm the remaining balance and final file handoff. A verification build may contain agreed identification marks; discuss those before work starts. Check the source and dependencies in the final handoff against the delivery list.