GSTIN recording requirement ensures customs-GSTN reconciliation for import/export IGST credit and refund at non EDI sites. Non EDI customs sites must capture BE/SB details for GSTN cross validation: use a site specific three digit series within six digit BE/SB numbers, record GSTIN or valid provisional ID and Census based state code, and use an offline data capture utility (until widely available, follow interim manual measures) so ICES can validate IGST credit/refund claims with GSTN. Export invoices must bear the GST invoice endorsement and IGST refund or export proof will be processed only after EGM number and date confirm completion.