[ibr-053]-If the Tax accounting currency code (ibt-006) is present, then the Invoice total Tax amount in accounting currency (ibt-111) MUST be provided.
ibr-053
/ubl:Invoice | /cn:CreditNote
every $taxcurrency in cbc:TaxCurrencyCode satisfies exists(//cac:TaxTotal/cbc:TaxAmount[@currencyID=$taxcurrency])