Payment errors often begin before finance sees an invoice. A supplier may have been created without checking, an order may lack approval or a delivery discrepancy may remain unresolved. Review the complete chain from supplier setup to final bank release. A control that only checks the last amount cannot establish whether the business authorised the purchase or actually received what it is paying for.
Define who can request a purchase and who approves the commitment. Keep orders or equivalent evidence proportionate to the business. Record receipt of goods or acceptance of services separately from invoice processing where possible. The comparison should identify differences in quantity, price and terms, with a named person responsible for resolving them. An invoice should not become its own evidence that the underlying service was delivered.
Supplier records need controlled maintenance. Verify new payment details through an established contact route, particularly when a request arrives by email. Keep approval evidence and restrict who can change the master data. Access restrictions and payment approval serve different purposes: a carefully authorised payment can still be wrong if someone has changed the recipient's account without an effective check elsewhere in the process.
In a hypothetical construction business, a regular supplier emails replacement bank details shortly before a payment run. The team verifies the change using a previously established contact rather than the number in the new message. It also checks the invoice against the order and receipt record. These are separate controls over recipient and transaction, addressing different risks that one signature alone would not fully cover.
Build checks for duplicate invoices, credit notes and partial payments. Review exceptions before release, documenting why a mismatch is acceptable or what correction is needed. Avoid informal approvals that cannot later be linked to the invoice. Where urgent purchases bypass the normal route, require a visible exception record and followup rather than allowing urgency to become an unrestricted alternative purchasing process used by the whole team.
Periodically test completed transactions across the chain and investigate recurring breaks. Report findings with practical actions and clear responsibility. A purchasing control review can help identify whether errors arise in authorisation, receipt, supplier maintenance or payment execution, allowing the business to improve the right stage instead of repeatedly correcting invoices after money has already left the bank account.