Fix the scope of the review
Begin with one client, one warehouse, and one closed billing period. Identify the agreement version and the existing invoice being reviewed. Record currency, timezone, and the source files used.
Confirm coverage before looking at amounts. Shipment exports should cover the period; storage evidence should satisfy the agreed storage method; VAS should carry the required completion and approval references. List gaps as explicit blockers.
Work the exceptions with operations
Separate quantities, rates, timing, credits, and unmatched invoice lines. A quantity difference may need an operational source check, while an ambiguous allowance may need a commercial agreement decision. Give each issue an owner who can resolve the underlying question.
Write down what would resolve the exception. “Check invoice” is less useful than “confirm whether work order WO-0926-041 was included on another invoice line.” Preserve the evidence reviewed and the rationale for accepting a difference.
Approve a reproducible result
Approval should refer to a specific run and its source and agreement versions. If the evidence changes after approval, preserve the original result and create a linked correction or replacement version through the agreed process.
A close record should answer four questions: what was approved, which evidence supported it, who approved it, and what changed afterward. That makes the next billing conversation easier, even when the answer is that an amount remains unknown.