Retrospective amendment validates prior customs notification actions and reclassifies stearic acid under a different tariff heading. The clause authorises a retrospective amendment of notification G.S.R. 785(E) under the Customs Act and Customs Tariff Act to reclassify stearic acid as specified in the Third Schedule, deems the notification amended from the Schedule date, and declares any actions taken under the original notification to be valid as if the amendment had always been in force; it further deems the Central Government to have had the retrospective power to make that amendment at all material times.