This feature enables consumption of "Original document is credit note" (IsOriginalDocumentCreditNote) field from TaxTrans_Reporting table by TaxTransDeclarationDetailsView.IsCreditNote used in VAT declarations. "Original document is credit note" field in TaxTrans_Reporting table is calculated and stored during sales tax transaction posting. It utilizes exiting methods to determine a credit note property based on the source document of tax transaction (e.g., CustInvoiceJour.creditNote()). If there is no such method, or there is no original document for tax transaction, system applies a method to determine if tax transaction is a credit note or not based on the tax transaction properties like amount sign, tax direction, reverse charge criteria. To guarantee that IsCreditNote field in TaxTrans_Reporting table contains necessary for reporting data, we recommend running Program > General ledger > Sales tax > Consistency check for TaxTrans_Reporting (Modules > System administration > Periodic tasks > Database > Consistency check) for the reporting period you are going to generate VAT declaration.