FX-SCH-A-000042: The VAT total in the invoice currency may appear only once

What it means

Within ram:SpecifiedTradeSettlementHeaderMonetarySummation (BG-22), this rule allows at most one ram:TaxTotalAmount with currencyID equal to ram:InvoiceCurrencyCode (BT-5) in the enclosing settlement section. It does not require such a total or check its value. Totals with a different currencyID are outside this count; that alone does not establish that they are valid VAT accounting currency totals (BT-111). It applies to all five profiles of Factur-X 1.09 and ZUGFeRD 2.5.

Why it matters

The invoice-currency VAT total has one defined place in the document totals. A separate VAT accounting currency total has a different purpose and needs its own correct currency and amount.

How to fix it

Check the ram:TaxTotalAmount entries in your document totals and keep the correct BT-110 entry with currencyID matching the actual invoice currency. Remove repeated entries rather than changing their currency codes to avoid this count. Include a BT-111 total only if it genuinely applies and your profile allows it. Export again and recheck.

The rule as published

Element variant 'ram:TaxTotalAmount[@currencyID=../../ram:InvoiceCurrencyCode]' may occur at maximum 1 times.

Where this rule applies