PEPPOL-EN16931-R055

The tax total in the invoice currency and the tax total in the accounting currency must carry the same operational sign. Both describe the same amount, only in two currencies.

Severity: Error
Applies to: CII, UBL
Rule set: v2026-01-31

Official rule text

Invoice total VAT amount and Invoice total VAT amount in accounting currency MUST have the same operational sign

Why does PEPPOL-EN16931-R055 happen?

On credit notes with negative amounts the sign gets flipped in one place and not the other — typically because the conversion into the reporting currency runs through a service that returns an absolute value.

How do you fix PEPPOL-EN16931-R055?

Convert from the signed amount rather than handling sign and magnitude separately. What is checked is the two cbc:TaxAmount values in the cac:TaxTotal blocks in UBL, and the corresponding amounts in CII.

In the XML

A UBL fragment. The CII path is named above — same change, different element names.

Fails

<cac:TaxTotal>
  <cbc:TaxAmount currencyID="EUR">-190.00</cbc:TaxAmount>
</cac:TaxTotal>
<cac:TaxTotal>
  <cbc:TaxAmount currencyID="SEK">2090.00</cbc:TaxAmount>
</cac:TaxTotal>

Fixed

<cac:TaxTotal>
  <cbc:TaxAmount currencyID="EUR">-190.00</cbc:TaxAmount>
</cac:TaxTotal>
<cac:TaxTotal>
  <cbc:TaxAmount currencyID="SEK">-2090.00</cbc:TaxAmount>
</cac:TaxTotal>

NormAPI provides technical validation, not tax or legal advice.