FX-SCH-A-000057
The VAT category tax amount (BT-117) in a VAT breakdown (BG-23) where VAT category code (BT-118) is "Standard rated" shall equal the VAT category taxable amount (BT-116) multiplied by the VAT category rate (BT-119).
What the rule checks
As the rule set's publisher wrote it. The rule runs on every element the context matches, and fails where the test is false; the validator reports the line of that element.
[BR-S-09] The VAT category tax amount (BT-117) in a VAT breakdown (BG-23) where VAT category code (BT-118) is "Standard rated" shall equal the VAT category taxable amount (BT-116) multiplied by the VAT category rate (BT-119).
//ram:ApplicableHeaderTradeSettlement/ram:ApplicableTradeTax/ram:CategoryCode[.='S']
(abs(xs:decimal(../ram:CalculatedAmount)) - 1 < round(abs(xs:decimal(../ram:BasisAmount)) * ../ram:RateApplicablePercent) div 100 ) and (abs(xs:decimal(../ram:CalculatedAmount)) + 1 > round(abs(xs:decimal(../ram:BasisAmount)) * ../ram:RateApplicablePercent) div 100 )
Checked with Factur-X / ZUGFeRD BASIC