Duty payment schedule: amended fortnightly deadlines with special March pro rata payment and monthly exemption alternative. Amendments require manufacturers not under the value based annual exemption to discharge excise duty on a fortnightly schedule with specified due dates, and impose a special March pro rata interim payment by 31 March followed by settlement or adjustment by 20 April; manufacturers claiming the value based exemption must pay monthly by the fifteenth day of the succeeding month. Duty is deemed discharged only when credited to the Central Government account by the specified due date.