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What the three-way match lets through.

Neil reads each supplier invoice and holds it against the PO, the receipt and every other invoice, to find what passes one at a time: a price inside tolerance, the same lines under a new number, a return with no credit, a small charge repeated. AP decides.

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  1. Pencil drawing: a seal at a desk peers over three tall leaning stacks of paper, one slip on top with a red corner fold.

    Matched, and paid.

    A price inside tolerance, a small charge and a new invoice number each pass the match, one invoice at a time.

  2. Pencil drawing: a seal runs a long ruler across three sheets of paper side by side, a red pencil line along its edge.

    Neil reads every invoice.

    Each line against the PO and the receipt, and each invoice against the others.

  3. Pencil drawing: a seal holds up two identical sheets, one crossed through in red, while a second seal looks startled.

    It finds what only shows across invoices.

    The same lines under a new number, a price a little high every time, a return nobody credited.

  4. Pencil drawing: a seal signs a sheet while a second seal hands an envelope with a red stamp to a third at a door.

    AP acts.

    Neil drafts the letter to the supplier. AP takes the invoice out of the run and sends it.

What passes one invoice at a time.

Each of these cleared AP’s match. None of them should have been paid as billed.

  • PO
    $7.95
    Billed
    $8.10

    A price just inside tolerance.

    1.9%, inside AP’s 2%: $11,475 on two invoices.

  • First invoice
    AW-77610
    Billed again
    AW-77702

    The same invoice, renumbered.

    Line for line: $85,488, due to pay 25 November.

  • Returned
    150 kg
    Credited
    Nothing

    A return nobody credited.

    Both invoices paid: $5,775 owed back.

  • Each invoice
    Under $500
    8 invoices
    $1,181.25

    A small charge, repeated.

    An energy surcharge that isn’t on any PO.

69 invoices, held against each other.

Real Seal screens from a full test run: Acme Medical’s AP register and supplier invoices, as of 06:00 on 5 November 2026.

  1. 1

    Each of these passed the match.

    All 69 invoices in the AP register, held against the PO, the receipt and each other.

    The invoice matching board in Seal: four findings that need a decision, each with who decides and what Neil proposes, above a table of every invoice with its PO, date, amount and how AP matched it.
    1. What got throughA price inside tolerance, an invoice billed twice, a return not credited, a small charge repeated.
    2. What Neil proposesThe credit to ask for, the invoice to take out of the run, the charge to question.
    3. Every invoiceSupplier, PO, date, amount, and how AP’s match treated it.
  2. 2

    The same invoice, renumbered.

    AW-77702 repeats AW-77610 line for line: $85,488, due to pay 25 November.

    Neil’s finding in Seal that Acme Wire’s invoice AW-77702 re-bills AW-77610, with the invoice opened beside it showing the same PO, quantities and prices, dated 26 October and due 25 November.
    1. Opened beside the findingDated 26 October, due 25 November. The same PO, quantities and prices as AW-77610.
    2. Why it got throughAP’s duplicate check looks at the invoice number, and this one was keyed manually.
    3. What Neil proposesTake it out of the 25 November run, and ask Acme Wire to void it.
  3. 3

    A price just inside tolerance.

    $8.10 against the PO’s $7.95 is 1.9%, inside AP’s 2%: $11,475 on two invoices.

    Neil’s finding in Seal that Acme Fluoropolymers bills PTFE liner at $8.10 against the PO’s $7.95 on two invoices, with who decides, the proposal, the evidence and the working.
    1. Why it passedEach invoice posted and was paid. Nothing in the mailbox or the POs agrees the higher price.
    2. What Neil proposesA credit of $11,475, and the next invoice held to $7.95.
    3. What it rests onBoth invoices, both register rows, both receipts and the open PO.
  4. 4

    The letter, drafted.

    Which invoice, which PO and what to do about it. AP edits it and sends it.

    A draft email in Seal to Sandra Ng at Acme Wire, linked to its finding and not sent, saying AW-77702 bills the same lines of PO 4500-1162 as AW-77610 and asking for it to be voided.
    1. What it saysIt won’t be paid twice: void it, or say what it’s for.
    2. Linked to its findingBoth invoices stay one click from the letter.
    3. Not sentNothing goes until a person sends it.

What passes the match gets paid.

Duplicates get through the controls of large organisations, and the window to catch them is short.

Past the controlsPublished figures

819
duplicate payments, £11 million, found across English public bodies from April 2022 to March 2024.National Fraud Initiative report, 2022 to 2024
$1.9 million
in duplicate payments recovered or being recovered at Amtrak, where staff processed known duplicates despite system warnings.Amtrak Inspector General, 2013
15.0 days
median from receiving an invoice to paying it: the time there is to catch one.APQC, 2,227 organisations

With NeilTest run, 5 November 2026

69
invoices worth $3.4 million from 9 suppliers, held against POs and receipts.Acme Medical’s AP register and invoice PDFs
4 of 4
planted problems found.Built into the test run for Neil to find
19 of 19
numbers in the findings match the answer key.Prices, amounts and dates
0 of 6
decoys raised, among them a short-pay already settled and an invoice two cents out.Built into the test run for Neil to set aside

AP decides what gets paid.

Neil reads, compares and drafts. It never approves, holds or pays an invoice, or changes the ledger. Each finding keeps the invoices, receipts and register rows it rests on.

See how supplier email reaches the order

Summary

The problem
A three-way match looks at one invoice at a time. A price inside tolerance, a small unagreed charge and an invoice re-keyed under a new number each pass it, and each gets paid.
Seal’s approach
Neil reads every invoice, keeping each line with its words, then compares in code: against the PO’s price and the receipt, and across invoices for repeats, missing credits and charges no agreement carries.
What changes
AP sees what to take out of the next run and what to ask for back, with the letters drafted.
Where to start
Six months of invoices with the AP register, receipts, POs and your match rules. Book a demo.

1The match passes one invoice at a time.

A three-way match holds an invoice against its PO and receipt. Most ERPs allow a tolerance on price, a limit under which a charge posts without review, and a duplicate check on the invoice number. Each is sensible alone. A supplier 1.9% high every time, a surcharge under the limit on every invoice, or the same lines under a new number each pass, and only show when invoices are read together.

Across English public bodies, 819 duplicate payments worth £11 million were found from April 2022 to March 2024.¹ At Amtrak, staff processed known duplicates despite system warnings, and about $1.9 million was recovered or being recovered.² The median time from receiving an invoice to paying it is 15.0 days, so the window to catch one is short.³

2Read each invoice. Compare in code.

Neil reads every invoice: its number, PO, each line and charge, each kept with the words it came from. Code does the rest: the amount against the receipt at the PO’s price, the same lines billed under another number, returns with no credit, and charges no PO or agreement carries.

369 invoices at Acme Medical.

On Thursday 5 November 2026, fictional Acme Medical’s register held 69 invoices worth $3.4 million from 9 suppliers. Neil raised four things, and set aside six that looked wrong and weren’t.

SupplierWhat passedAmount
Acme WireAW-77702 re-bills AW-77610, keyed by hand, due to pay 25 November$85,488.00
Acme Fluoropolymers$8.10 against the PO’s $7.95 on two invoices, inside AP’s 2%$11,475.00
Acme Compounding150 kg returned, both invoices paid, no credit memo$5,775.00
Acme PolymersAn energy surcharge on 8 invoices, each under AP’s $500 limit, on no PO$1,181.25

4AP decides.

Neil drafts the letter to the supplier. AP takes an invoice out of the run, holds a payment and sends the letter. Neil never approves, holds or pays an invoice, or changes the ledger.

5Start with six months of invoices.

Bring six months of invoices with the AP register, receipts, POs and your match rules. What Neil finds can be checked against the ledger the same day.

References

  1. 1UK Cabinet Office, National Fraud Initiative report 2022 to 2024: 819 duplicate payments totalling £11 million, £10.3 million recovered. GOV.UK
  2. 2Amtrak Office of Inspector General, OIG-A-2013-018, 2013: about $1.9 million in duplicate invoice payments recovered or in the process of recovery. Amtrak OIG
  3. 3APQC, measure 100575, sample 2,227, read from an archive copy of 11 February 2026. APQC

ACapabilities

CapabilityWhat it covers
Invoice readingRead each invoice’s number, PO, lines and charges, each kept with its words.
Price checkCompare each line in code with the receipt at the PO’s price, across a supplier’s invoices.
Duplicate checkFind the same lines billed under another number, whatever the number.
Return checkFind returns with no credit memo, and what is owed.
Charge checkFind charges no PO or agreement carries, added up across invoices.
Drafted lettersDraft the letter to the supplier for AP to edit and send.

BConnected records

Entity
What it records
Kind
Supplier Invoice
An invoice as received, with what Neil read from it.
type
Purchase Order Line
What was agreed: quantity and price.
type
Goods Receipt
What arrived, or went back.
type
Invoice Finding
What passed the match that shouldn’t have, and what AP decided.
type

CQuestions and answers

Does Neil pay or hold invoices?

No. It finds them and drafts the letter. AP holds, pays and writes to the supplier.

Does it replace our AP automation?

No. Your match runs as it does now. Neil reads what passed it, across invoices.

Will it flag every small difference?

No. A two-cent rounding, an agreed freight charge and a short-pay already settled are set aside. Your match rules say what counts.

What data does a proof need?

Six months of invoices with the AP register, receipts, POs and your match rules. No live access is needed.

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