4.11 Good to know — procurement

The invoice never rewrites the receipt. When the two disagree, the difference goes to a named variance account — price difference and exchange difference kept apart — where everyone can see it, rather than into stock or margin where nobody can.
Matching is same-currency. A receipt is cleared by invoices in its own currency; cross-currency settlements are a conversation with your accountant, not an accident of matching.
An estimate is a placeholder with a deadline, not a guess you are stuck with. If the Estimates vs Actuals worklist is growing old, the problem is paperwork flow, not the system.
Unwind in order. Adjustments before the receipt they stand on; the receipt before the order it fulfils. The chain reverses the way it was built.
Quote validity protects both parties. Inside it, the supplier's price is committed; outside it, re-pricing is a renegotiation, and the order makes that boundary explicit instead of arguable.
A payment's unapplied remainder is credit with the supplier, visible on their record — money you have already spent, working for you on the next invoice.
The supplier's invoice number is their identity for the document. Enter it faithfully on every purchase invoice; it is the reference every dispute will be conducted in.