UBL-CR-176: The seller's tax scheme should not include a currency code

What it means

In the seller's tax details, EN 16931 only reads the identifier of the tax scheme (cbc:ID). The currency of an invoice is given once, as the invoice currency (BT-5), with a separate VAT accounting currency (BT-6) when the VAT is reported in another currency. This rule fails whenever cbc:CurrencyCode is present inside cac:TaxScheme in the seller's tax details, even if it is empty.

Why it matters

This rule is a warning, so the invoice is still accepted. The recipient's software takes the currency from BT-5 and BT-6 and ignores the one in the tax scheme. It is worth fixing when the currencies differ, because only one of them is read and it may not be the one you meant.

How to fix it

In your invoicing software, set the currency on the invoice itself and, if VAT is reported in a second currency, in the VAT currency field. If you build the XML yourself, delete cbc:CurrencyCode from cac:AccountingSupplierParty/cac:Party/cac:PartyTaxScheme/cac:TaxScheme. Check that cbc:DocumentCurrencyCode is filled in.

The rule as published

A UBL invoice should not include the AccountingSupplierParty Party PartyTaxScheme TaxScheme CurrencyCode

Where this rule applies