Reversal of Modvat credit: certification required confirming formula-based reversal and interest payment before Customs closure. Reversal of Modvat credit for exports under the Value Based Advance Licence requires Assistant Commissioner verification and a certificate stating that credit reversal and interest payment conform to the Board's formula; non-conforming reversals must be quantified by a Cost Accountant nominated under section 14A before certification, part reversals or part interest payments must be clearly recorded, and actual-basis revisions require Cost Accountant verification prior to issuance.