Matching of input tax credit may add to recipient output liability unless supplier corrects, with interest refundable. Matching inward supply details with supplier returns, applicable customs duty, and duplication checks governs final acceptance of input tax credit. Discrepancies or duplications are communicated; unresolved discrepancies and duplications are added to the recipient's output tax liability. The recipient may reduce such additions if the supplier rectifies returns within the prescribed time. Interest is payable on amounts added from the date credit was availed, and accepted reductions trigger interest refund to the electronic cash ledger, subject to a cap linked to interest paid by the supplier.