XV-SA-11
The total with VAT in the QR code (tag 4, …) is neither the invoice's TaxInclusiveAmount (…) nor, after prepayments, its PayableAmount (…).
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.
/*/cac:AdditionalDocumentReference[cbc:ID = 'QR']
not($readable) or $fields[5] = '' or empty($total) or sa:dec($fields[5]) = ($total, $payable)
Checked with Saudi Arabia ZATCA Tax Invoice (UBL), Saudi Arabia ZATCA Simplified Tax Invoice (UBL)