GST return reconciliation: system matches GSTR-1/2 to GSTR-3B, requiring additional ledger debits or ITC credits as needed. System-based reconciliation requires suppliers to file FORM GSTR-1 and recipients to finalise FORM GSTR-2 using auto-populated FORM GSTR-2A; the portal auto-drafts FORM GSTR-3 and computes revised tax payable in Table 12. Where reconciled tax payable exceeds payments shown in FORM GSTR-3B, additional tax must be paid by debiting the electronic cash or credit ledger with interest under section 49; excess eligible ITC in FORM GSTR-2 is credited to the electronic credit ledger upon submission of FORM GSTR-3 and may be applied to increased tax liabilities.