Excise duty exemption for Sikkim manufacturers tied to value addition, with procedural refund and CENVAT credit conditions. Exemption from central excise duty for goods cleared from units in Sikkim is limited to the portion of duty equivalent to value addition, calculated either by prescribed percentage rates in a tariff-linked Table or, on application and verification, by a Commissioner-fixed special rate reflecting actual value addition. Claimants must utilize CENVAT credit first (where applicable), submit monthly statements of duty and CENVAT utilisation, and obtain refunds or account-current credits under specified timelines and verification, with provisions for provisional refunds, reversals of excess credit and recovery of irregularly availed amounts.