Rule at a Glance
| ID | Severity | Context (XPath) |
|---|---|---|
| Series ref. BR-75 | Fatal (error) | cac:InvoiceLine/cac:DespatchLineReference/cac:DocumentReference/cbc:ID | cac:CreditNoteLine/... |
| Schematron ID: ibr-092 | Field: ibt-184 (line) and ibt-016 (document) — Despatch advice reference | ||
Classification
Syntax & Integration — a mutual exclusion between two places the same reference could legitimately sit.
What the Rule Is Checking
The rule fires once for every invoice line that carries a despatch advice reference. When it fires, it asserts count(//cac:DespatchDocumentReference) = 0: the document must contain no despatch reference at header level anywhere.
The double slash makes the search absolute across the whole document rather than relative to the line being processed, so a single header-level despatch reference will fail the rule once for every line that carries its own. One structural mistake produces a page of validation errors that all point back to the same element.
Why This Rule Exists
A despatch advice reference is how the buyer links an invoice to the goods that arrived. That link drives the three-way match, and the match only works if there is one unambiguous answer to the question of which delivery this invoice relates to. A header reference says the entire document relates to one despatch. Line references say each line relates to its own. Both present, and the receiving system has to choose which one to believe, and different ERPs choose differently.
The practical consequence sits on the buy side. Under the UAE five-corner model, Corner 2 reports the supplier’s Tax Data to Corner 5 at or near the point of issuance and Corner 3 reports again on successful technical validation, so the authority can assemble a view of the purchase before the buyer has finished assessing it. That interval is the Inbound Tax Assurance Gap™ — the time between authority visibility of a buyer-attributed transaction and the buyer completing commercial validation, AP posting and input tax entitlement assessment. An invoice that clears Peppol validation while carrying an ambiguous reference structure stalls the matching step and holds that gap open longer. Forcing a single level removes the ambiguity at source.
Standard / Code List
No code list applies. The despatch advice reference is a free-text identifier, and its value is whatever the seller’s despatch document is numbered.
UAE Data Example
PASSES ✓ — consolidated invoice covering three deliveries, referenced per line, with nothing at header level:
<cac:InvoiceLine>
<cbc:ID>1</cbc:ID>
<cac:DespatchLineReference>
<cac:DocumentReference>
<cbc:ID>DN-2027-004417</cbc:ID>
</cac:DocumentReference>
</cac:DespatchLineReference>
</cac:InvoiceLine>An invoice covering a single delivery passes equally well with one header-level cac:DespatchDocumentReference and no line references at all. The rule does not prefer one pattern over the other.
FAILS ✗ — the same line references retained while the header reference is also populated:
<cac:DespatchDocumentReference>
<cbc:ID>DN-2027-004417</cbc:ID>
</cac:DespatchDocumentReference>This fails even when the header value duplicates one of the line values. The rule tests presence, not agreement.
What Your ERP / IT Team Must Ensure
- Decide the mapping level once, per document type, rather than letting it follow whatever the source billing document happened to populate.
- Where invoices are generated from consolidated delivery runs, suppress the header despatch reference in the mapping whenever any line reference is written.
- Watch for templates that populate the header field as a convenience copy of the first line — a common pattern in SAP billing document output that passes internal checks and fails at Corner 2.
- Apply the same discipline to the credit note flow, since the rule context covers
cac:CreditNoteLineon identical terms. - Confirm with your buyers which level their AP matching engine reads, because passing validation and being matchable are separate outcomes.
Related Rules
ibr-096 limits the header-level despatch advice reference to a single occurrence when it is used. Together the two rules leave exactly three valid shapes: one header reference, line references only, or no reference at all.