(1) The Commissioner may, either of his own motion or on application made by an assessee in this behalf, call for the record of any proceeding under this Act in which an order has been passed by any authority subordinate to him, and may make such inquiry, or cause such inquiry to be made, and, subject to the provisions of this Act, pass such order thereon, not being an order prejudicial to the assessee, as the Commissioner thinks fit: Provided that the Commissioner shall not revise any order under this sub- section in any case--
(a) where an appeal against the order lies to the Appellate Assistant Commissioner or to the Appellate Tribunal, the time within which such appeal can be made has not expired or in the case of an appeal to the Appellate Tribunal the assessee has not waived his right of appeal;
(b) where the order is the subject of an appeal before the Appellate Assistant Commissioner or the Appellate Tribunal;
(c) where the application is made by the assessee for such revision, unless--
(i) the application is accompanied by a fee of twenty- five rupees; and
(ii) the application is made within one year from the date of the order sought to be revised or within such further period as the Commissioner may think fit to allow on being satisfied that the assessee was prevented by sufficient cause from making the application within that period; and
(d) where the order is sought to be revised by the Commissioner of his own motion, if such order is made more than one year previously. Explanation.-- For the purposes of this sub- section,--
(a) the Appellate Assistant Commissioner shall be deemed to be an authority subordinate to the Commissioner; and
(b) an order by the Commissioner declining to interfere shall be deemed not to be an order prejudicial to the assessee.