The invoice total without VAT MUST be equal to the VAT category taxable amount if the VAT category code is reverse charge
//cac:TaxTotal[cac:TaxSubtotal/cac:TaxCategory/cbc:ID = 'AE'](sum(cac:TaxSubtotal[cac:TaxCategory/cbc:ID = 'AE']/cbc:TaxableAmount) = (../cac:LegalMonetaryTotal/cbc:TaxExclusiveAmount))