24.  Rectification of mistakes :-

       (1) The Commissioner may, at any time within two years from the end of a financial year in which any order passed by him has been served, on his own motion, rectify any mistake apparent on the record, and shall within the said period or thereafter rectify any such mistake which has been brought to his notice within the said period, by any person affected by such order:

                              Provided that, no such rectification shall be made if it has the effect of enhancing the tax or reducing the amount of a refund or interest payable on refund, unless the Commissioner has given notice in writing in the prescribed form to such person of his intention to do so and has allowed such person a reasonable opportunity of being heard. An application for rectification shall not be rejected on the ground that there is no mistake apparent on record unless the person concerned has been given a reasonable opportunity of being heard :

                              Provided further that, where a dealer has applied in the prescribed form within the said period of two years for rectification of the said order and specified in his application, the quantum by which the amount payable as per the said order should be reduced, then the Commissioner shall, without prejudice to the other provisions of this Act including levy of interest, stay the recovery of such quantum till the disposal of the application for rectification.

       (2)  Where any dealer or person has recorded in his books of accounts or, as the case may be, has claimed in the returns that no tax is payable or that the tax is payable at a reduced rate on any transaction of sale on account of any declaration or certificate to be received from the purchasing dealer or person and he has not produced such certificate or declaration before the passing of the order of assessment under section 23 for any reason whatsoever in which assessment order the claim is disallowed, then at any time within two years from the end of the financial year in which the said order has been served, he may, unless he has filed an appeal against the said order, apply to the Commissioner for rectification of the order on the ground that he has received such declaration or certificate and is in a position to produce the same and thereupon the Commissioner shall hold such inquiry as he may deem fit and after hearing the applicant, rectify the assessment order if the application is in order:

                                 Provided that, in respect of any assessment order sought to be rectified, only one application for rectification shall be entertained under this sub-section.

       (3)  The provisions of sub-section (1) shall apply mutatis mutandis to the rectification of a mistake by the Tribunal or an appellate authority as they apply to the rectification of a mistake by the Commissioner :

                                  Provided that, where any matter has been considered and decided in any proceeding by way of appeal or review in relation to any order or part of an order, the authority passing the order of appeal or review, may, notwithstanding anything contained in this Act, rectify the order or part of the order on any matter other than the matter which has been so considered and decided.

       (4)  Where any such rectification has the effect of reducing the amount of the tax or penalty or interest or the amount of forfeiture, the Commissioner shall, refund any amount due to such person in accordance with the provisions of this Act.

       (5)  Where any such rectification has the effect of enhancing the amount of the tax or penalty or interest or the amount of forfeiture or reducing the amount of the refund, the Commissioner shall recover the amount due from such person in accordance with the provisions of this Act.