Retrospective amendment to excise notification validates past actions and enables adjustment and refund of declared duty credits. The provision effects a retrospective amendment to the notification under rule 57AK, deeming actions taken under the original notification to have been valid as if the amendment had always been in force. It mandates allowance of declared duty credits previously disallowed and requires refund of collected declared duty credits that would not have been collected under the amended notification. Refund claims must be made within six months from the Finance Bill, 2002 receiving Presidential assent and apply notwithstanding section 11B of the Central Excise Act.