For Danish Suppliers if the PaymentID is prefixed with 71# or 75# the 15-16 digits instruction Id must be added to the PaymentID eg. "71#1234567890123456" when payment Method equals 93 (FIK)
ubl-invoice:Invoice[$DKSupplierCountry = 'DK' and $DKCustomerCountry = 'DK']/cac:PaymentMeans
not((cbc:PaymentMeansCode = '93') and ((substring(cbc:PaymentID, 1, 3) = '71#') or (substring(cbc:PaymentID, 1, 3) = '75#')) and not((string-length(cbc:PaymentID) = 18) or (string-length(cbc:PaymentID) = 19)) )