Deemed excise duty payment permitted for specified inputs and manufacturers as full discharge subject to conditions and interest. The amendment authorises notification of inputs deemed to have excise duty paid under section 3A and allows credit accordingly; it revises rules 96ZO and 96ZP to permit specified manufacturers to discharge duty liabilities by prescribed monthly payments treated as full and final discharge, subject to exclusions from section 3A benefits, pro rata adjustments for capacity changes, extended payment dates for September, interest on outstanding sums, and reconciliation where capacity is provisionally determined and later finalized. The preamble is retrospectively amended to invoke section 3A read with section 37.