Each Document level charge (ibg-21) shall be categorized by Document level charge tax category code(ibt-102)and Document level charge tax rate (ibt-103).
/cac:AllowanceCharge[cbc:ChargeIndicator=false()]
exists(cac:TaxCategory[cac:TaxScheme/normalize-space(upper-case(cbc:ID))='VAT']/cbc:ID) and exists(cac:TaxCategory[cac:TaxScheme/normalize-space(upper-case(cbc:ID))='VAT']/cbc:Percent)