[IBR-036-OM] - Invoicing period Start date (IBT-073) and Invoicing period end date (IBT-074) provided must belong to the same calendar month where Invoice transaction type code (BTOM-001) is a summary invoice (XXXX1XXXXXXXXXXXXXXX).
IBR-036-OMubl:Invoice | cn:CreditNotenot($isSummary) or (substring(cac:InvoicePeriod/cbc:StartDate,1,7) = substring(cac:InvoicePeriod/cbc:EndDate,1,7))