BR-AG-08:IPSI taxable amount calculation error
The IPSI taxable amount in the VAT breakdown does not match the calculated sum of line amounts plus charges minus allowances for the IPSI category.
Engine Classification
Recalculate IPSI taxable amount from sum of line amounts per EN16931 BR-AG-08
Confidence: 85% · Applied automatically in pipeline
What is BR-AG-08?
BR-AG-08 is a fatal validation rule defined in the EN 16931 specification. It validates the TaxableAmount element under TaxSubtotal[cac:TaxCategory > ID='M'] in the UBL invoice XML.
When this rule fires, the invoice is non-compliant and will be rejected by Peppol access points and national validation services. The sending system receives a rejection response and the invoice does not reach the buyer.
Target path: //cac:TaxTotal/cac:TaxSubtotal[cac:TaxCategory/cbc:ID='M']/cbc:TaxableAmount
Why This Error Matters
Invoice will be rejected. IPSI (Ceuta/Melilla indirect tax) transactions must follow specific rules for Spanish territory tax compliance.
BR-AG-08 is a hard failure. Invoices that trigger this rule are rejected at the access point and never reach the recipient. In Peppol networks, this means your sending system receives an MLR (Message Level Response) with a rejection status. The invoice must be corrected and re-sent, adding delay to your payment cycle.
Invoice Navigator can automatically correct this error in your pipeline. The fix is applied with full audit evidence, so your compliance trail remains intact.
Validator Behavior
- ·Causes invoice rejection
- ·Error returned: BR-AG-08
- ·Specification: EN 16931
How to Fix It
Calculate line total
Sum all Invoice line net amounts (BT-131) where VAT category is IPSI (M)
Add charges
Add document level charge amounts (BT-99) with IPSI category
Subtract allowances
Subtract document level allowance amounts (BT-92) with IPSI category
Update taxable amount
Set VAT category taxable amount (BT-116) to the calculated value
Before / After
<cac:TaxCategory> <cbc:Percent>999.99</cbc:Percent> <!-- Does not match expected calculation --> </cac:TaxCategory>
<cac:TaxCategory> <cbc:Percent>100.00</cbc:Percent> <!-- Matches expected calculation --> </cac:TaxCategory>
Technical Reference
//cac:TaxTotal/cac:TaxSubtotal[cac:TaxCategory/cbc:ID='M']/cbc:TaxableAmountCommon Causes
- ·IPSI taxable amount does not equal sum of line amounts
- ·VAT breakdown calculation mismatch for IPSI category
- ·Allowances/charges not properly included in IPSI base
- ·Rounding errors in IPSI taxable amount calculation
- ·Lines with IPSI rate not aggregated correctly
Seeing this in production? The API handles BR-AG-08 automatically. See the fix response →
See Also
Related Errors
Last updated: 27 February 2026
Handle BR-AG-08 Automatically in Your Pipeline
The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.