16. Revision.- The Central Government in the case of any decision order, not being a decision or order made in an appeal, made by the Director General, or the Director General in the case of any decision or order made by any officer subordinate to him, may on its or his own motion or otherwise, call for and examine the records of any proceeding in which a decision or an order imposing a penalty or redemption charges or adjudicating confiscation has been made and against which no appeal has been preferred, for the purpose of satisfying itself or himself, as the case may be, as to the correctness, legality or propriety of such decision or order and make such orders thereon as may be deemed fit: Provided that no decision or order shall be varied under this section so as to prejudicially affect any person unless such (a) has, within a period of two years from the date of such decision or order, received a notice to show cause why such decision or order shall not be varied, and (b) has been given a reasonable opportunity of making representation and, if he so desires, of being heard in his defence. | 