# The monthly P.O. reconciliation process that catches every discrepancy
Invoice number. Billing period. Amount paid. Units received. Cross-referenced monthly against QuickBooks.
This process sounds tedious. It is. It also caught a one-unit-short discrepancy on a Country Save order that would have become a supplier dispute three months later when the paper trail was cold and neither party could reconstruct what had actually happened.
One unit. A $300 difference on a single line item. Worth finding? Yes, because the pattern matters more than the amount. A supplier who ships one unit short on a small order will ship ten units short on a large one. And if you do not have a reconciliation process, you will not know until you run out of inventory two weeks earlier than planned and trace it back to a receiving record that was never verified.
The four columns
Every reconciliation sheet has four required columns per line item:
- Invoice number from the supplier
- Billing period the invoice covers
- Amount paid, sourced from QuickBooks
- Units received, sourced from the warehouse receiving report
The reconciliation is a match: does the invoice say you paid for X units during period Y, and does the receiving report confirm X units arrived?
When they match, the line is closed. When they do not match, the line gets flagged and investigated before the period is closed.
What discrepancies actually look like
They are rarely dramatic. The Army Painter reconciliation process surfaced an $119,809 outstanding balance in a supplier dispute. That one was not subtle. But the routine catches are quieter.
Invoice date mismatches are common: the supplier invoices on April 15, but the product did not arrive until April 22. Which billing period does that fall in? It depends on how your accounts payable system handles receive-date versus invoice-date accounting. If no one catches it, you end up with a discrepancy in your period-end balance that no one can explain six weeks later.
Partial deliveries are the most common source of ongoing confusion. A PO for 500 units ships in two batches: 300 in week one, 200 in week three. The supplier invoices for the full 500 on the first shipment date. Your receiving report shows 300 units received as of that date. The invoice and the receipt do not match, but the full PO will eventually match. Without line-by-line tracking, these partial delivery situations accumulate into a muddy payables balance where nobody is sure what is paid, what is owed, and what has been received.
The NanoClean reconciliation caught a clerical error on invoice dating where a payment was recorded in the wrong month by the supplier's billing team. Small. Correctable. Would have caused a mismatch in the annual accounts that someone would have spent three hours trying to resolve in January if no one had caught it in the monthly process.
How often to run it
Monthly, always. For clients with more than four active suppliers and regular PO activity, monthly is the minimum. Weekly reconciliation is not practical for most operations, but closing each month without a reconciliation means errors can stack for 30 to 60 days before anyone looks.
The process takes between 45 minutes and two hours depending on PO volume. It is not interesting work. It is the kind of work that buys you the right to be confident in your balance sheet.
What to do when an invoice does not match the receiving report
Do not adjust the accounting record until you know which side is wrong. Call the supplier, share the discrepancy, and ask for their documentation. If their records show 500 units shipped and your receiving report shows 499 received, the question is where the missing unit went: lost in transit, mislabeled at the warehouse, or a picking error at the supplier. The answer determines who absorbs the cost.
Suppliers who have been through this process before will have their own receiving records. The reconciliation conversation is straightforward: here is what our records show, here is what your invoice says, here is the specific discrepancy. That conversation takes ten minutes. The same conversation without clean records takes three weeks and ends in someone eating a loss they cannot prove.
The compounding argument
A single-month discrepancy is easy to write off. But discrepancies compound. A supplier who is consistently short by 1% on every order is stealing roughly $5,000 per year from a $500,000 purchasing operation. They may not be doing it deliberately. It may be a picking process issue on their end. Either way, you will not find it without the monthly reconciliation.
The month you skip is always the month something was wrong.
