FX-SCH-A-000108
In a Document level charge (BG-21) where the Document level charge VAT category code (BT-102) is "IGIC" the Document level charge VAT rate (BT-103) shall be 0 (zero) or greater than zero.
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-AF-07] In a Document level charge (BG-21) where the Document level charge VAT category code (BT-102) is "IGIC" the Document level charge VAT rate (BT-103) shall be 0 (zero) or greater than zero.
//ram:SpecifiedTradeAllowanceCharge[ram:ChargeIndicator/udt:Indicator='true']/ram:CategoryTradeTax[ram:CategoryCode = 'L']
ram:RateApplicablePercent > 0
Checked with Factur-X / ZUGFeRD BASIC