IGST refund officer interface allows verification and sanction of refunds in invoice-mismatch export cases, subject to exporter concordance evidence. An officer-interface alternative allows Customs officers to verify and reconcile invoice mismatches between GSTN records and Customs shipping bills for export IGST refund cases. Exporters must submit a certified concordance table mapping GST invoices to Shipping Bill invoices; the officer may accept, amend or reject entries, edit IGST amounts for short shipments, and enter the approved refund amount into Customs EDI. Refunds are calculated net of drawback, disabled for duplicated invoices once sanctioned, and paid electronically through PFMS. The mechanism applies only to shipping bills filed up to 31 December 2017 and only for cases flagged with the specified error code.