Penalty regime for excise defaults: revised percentage penalties, reduced rates for prompt payment, and adjustments on appeal. The substituted section 11AC establishes a revised penalty regime distinguishing inadvertent defaults from culpable conduct. For non intentional defaults the liable person faces a limited percentage penalty with an option to close proceedings by timely payment of duty and interest; reduced penalties are available for prompt payment after an officer's order. For defaults involving fraud, collusion or wilful mis statement the penalty equals the duty determined with transitional reduction for specified records, and appellate modification of duty proportionately adjusts penalty and interest with corresponding time limit provisions.