The habit every check shares
Hold every invoice, packing slip and counter ticket a vendor gives you during the month. When the statement arrives, go line by line and find the paper behind each one. Match the invoice number, then match the amount. A statement line with no paper, or paper with a different amount, gets a question before it gets paid.
Do this one vendor at a time. The parts house and the plumbing supply house never share a statement, so their piles never mix. Keep last month’s paid statement next to this month’s. You’ll need it.
The same line, billed twice
What it looks like: two statement lines with the same invoice number. Or two lines, same date, same amount, numbers one digit apart, because the counter keyed a ticket and the driver keyed it again at delivery. The carry-forward version is quieter: a line dated last month sitting in this month’s statement. Sometimes it says “balance forward.” Sometimes it’s an invoice you paid in March, back in April because your check posted after the statement cut.
The check: sort the statement lines by invoice number and duplicates stand together. Then read the date on every line against the statement period. Anything dated outside it gets checked against last month’s paid statement before you pay it twice.
Credits that never show up
What it looks like: the driver took a wrong-size fitting back and you have a return slip, maybe handwritten. Or the rep said on the phone that Tuesday’s damaged case would be credited. The statement shows the original invoice at full value and no credit line. The balance due is wrong by exactly that amount, and nothing on the page says so.
The check: treat a return slip or a promised credit as a document the vendor owes you. File it with that vendor’s invoices, not in a drawer. At statement time, look for a matching credit line. If there isn’t one, the statement total is wrong. Say so before paying. A promise with no paper is the one you’ll lose. Get a credit memo number, or at least an email, the day it’s made.
A price that moved between the quote and the bill
What it looks like: the quote said one price per yard of mulch. The invoice says another, because the yard’s price file updated on the first of the month. Or a property-maintenance vendor quoted a service call and billed labor at a different rate. Or the invoice and the statement disagree because a correction was keyed on one and not the other. The invoice number matches. Only the amount doesn’t.
The check: compare the statement amount to the invoice amount, not just the invoice numbers. A matching number with a different amount is easy to miss, because the number “checks out.” Where you have a quote, compare the invoice to it. On items you buy every month, glance at the unit price against last month’s. If it moved, you want to know, even when the move was legitimate.
A delivery with nothing behind it
What it looks like: a statement line with an invoice number and an amount, and you have no invoice for it. No packing slip, no ticket, no email. Maybe a tech signed for it in the field and the paper’s still in the truck. Maybe the distributor delivered a case to the wrong account. You don’t know, and that’s the point.
The check: don’t pay a statement line you can’t produce paper for. Ask the vendor for a copy. When it arrives, check it against what showed up: the count, the signature, the date. If the vendor can’t produce the invoice, the line comes off.
Line math that doesn’t add up
What it looks like: a quantity, a unit price, and an extended amount that isn’t the product of the two. Four filters at the unit price, extended at what five would cost. The same part, quantity and amount twice on one invoice. A core charge on a rebuilt part, and no core credit on any invoice since you sent the old one back. Handwritten counter tickets are a good place to look; the figures were keyed in a hurry.
The check: multiply every line with a quantity above one. Add the lines and compare to the subtotal, before tax and freight. On parts invoices, keep a running list of open core charges and expect a credit for each. The same part twice on one ticket is a question, not a charge.
A remit-to that isn’t the vendor
What it looks like: the invoice is right. Same logo, same items, same prices. The remit-to address is new, or the bank details, or an email arrived last week asking you to update your records. This is the one that may not be a mistake. The vendor may not know it’s happening.
The check: any change to where the money goes gets confirmed by phone, on the number you already had on file, never the one on the notice. Compare the remit-to on this invoice to the last one. Nothing on the new invoice, and nothing in the email, is authority for the change.
How InvoiceAnchor handles this
InvoiceAnchor does the statement-to-invoice match described above. Invoices, credit memos and counter tickets go to a private Inbox address and wait under the vendor’s name. When that vendor’s statement comes in, each line is matched to a held invoice, amounts side by side. Every unmatched line gets one label. “Amounts differ” is the invoice and the statement disagreeing on the same invoice number, with the difference shown. Your quote never enters the match; comparing invoice to quote stays with you. “Not on the statement” is the credit memo you sent that has no line. “Different month” is the carry-forward. “No invoice provided” is the line with nothing behind it, and under one-to-one matching it’s also how the second copy of a twice-keyed line shows up.
An optional line-item setting, off by default, reads the detail rows. It flags quantity-times-price errors and the same part, quantity and amount twice on one invoice. It also flags a price at least 10% (and at least $1) above the vendor’s most recent earlier price, a core charge open past 30 days, and a change in remit-to details between invoices. Add a late invoice and re-run; the re-run is free and never counts against your document allowance.
Questions that come up
Is vendor overbilling usually deliberate?
Treat every difference as a mistake until the paper says otherwise, and you’ll get it fixed faster. The one to treat differently is a change in remit-to details. Confirm that by phone every time.
Should I check invoices or statements?
Both. The invoice says what was billed for one delivery. The statement says what the vendor thinks you owe in total, and on a monthly trade account it’s what you pay against. Matching each statement line back to its invoice is where most of the checks in this guide happen. The line math, the quote comparison and the remit-to check happen on the invoice itself.
What do I do when I find one?
Don’t pay that line. Pay the rest. Tell the vendor in writing, with the invoice number, which line you’re not paying and why, and ask for a credit memo or a corrected statement. Note the same on your remittance so the payment is applied to the right invoices. Then hold the paper under that vendor until the credit shows up on a statement.