Document version inconsistency is a very common risk in foreign trade operations, especially when quotations, POs, and proforma invoices (PIs) need to go through several rounds of revision before confirmation. An effective approach is to preserve a PDF snapshot of each version sent out and keep both parties' copies in one place where you can directly compare differences between versions. This way, when the other party says their quantity is 500 boxes while your record shows 300, you can immediately pull up which version had the discrepancy and who made the change. Additionally, before shipment, it's recommended to do a final line-by-line review using the PI and PO to confirm that items, quantities, unit prices, and terms are all consistent, avoiding discovery of mismatches between documents and actual shipment after goods leave.