Accounts-payable processing errors result in millions of dollars in overpayments, duplicate payments, payments to wrong vendors, unused credit memos and missed discounts for U.S. corporations each year. Frequent corporate acquisitions and divestitures, expanding geographic territories, numerous local vendor relationships and multiple payables offices increase the likelihood of profit loss.

The following tips will ensure accurate accounts-payable processing: Avoid manual check requests. These are nonvalued transactions that require repeated attention from your payables staff and often lead to errors. We've conducted more than 2,000 accounts-payable audits and have recovered numerous payments that never appeared in the client's database because they were written or logged manually.

Never pay from a copy of an invoice. This is the most common cause of duplicate payments. Vendors traditionally mail invoices directly to the central accounts-payable department. In many cases, they send a copy of the invoice by fax if they have not received payment after 10 days. For companies that operate in several geographic regions with multiple local vendors, these duplicate invoices amount to hundreds of thousands of overpaid dollars.

Be consistent when entering invoice numbers into the accounts-payable system. Be sure that every vendor payment is directly tied to a specific invoice. Increasing use of advanced accounting software has left gaping holes in companies' payable processes. Inconsistent use of invoice numbers leads to payment lapses, duplicate payments, and overpayments. Avoid use of blanket purchase orders. Every payment must have a corresponding purchase order number and every purchase order number must have a corresponding payment. The key to error-free payment is careful tracking. Numbered purchase orders are essential to an orderly, trackable payables system.