Start with the commercial agreement
A warehouse event does not, by itself, tell you what to charge. A shipped order may carry an order-handling fee, extra-unit charges, packaging charges, or an exemption. The client agreement establishes which services are billable, which quantities matter, and when the rule applies.
A useful billing review begins by identifying the applicable agreement version, warehouse, currency, and billing period. Amendments need effective dates. Without that scope, two people can use the same export and reasonably arrive at different interpretations.
Separate activity from measurement
Activity describes what happened: an order shipped, a pallet arrived, or a preparation job was completed. A measurement translates that record into the quantity the agreement prices. Order count, physical units, distinct SKUs, and handling touches are different measurements.
For example, an agreement might include the first physical unit in every shipped order. Counting all units in the month and subtracting an allowance is not necessarily equivalent. Preserve the order-level evidence needed to explain additional units.
Compare before concluding
Review expected components against the existing invoice. A difference may reflect an agreed credit, timing, a missing reference, or a source correction. It is a question to investigate, not automatically a recoverable amount.
Assign each exception an owner and a next step. Keep unknown amounts separate from known differences. Close the period only when the evidence and commercial decisions support approval. Preserve the versions and source references so the approved result can be explained later.