(1) Before making the assessment, reassessment or recomputation under section 147, the Assessing Officer shall serve on the assessee a notice requiring him to furnish within such period, as may be specified in the notice, a return of his income or the income of any other person in respect of which he is assessable under this Act during the previous year corresponding to the relevant assessment year, in the prescribed form and verified in the prescribed manner and setting forth such other particulars as may be prescribed; and the provisions of this Act shall, so far as may be, apply accordingly as if such return were a return required to be furnished under section 139 : 

Provided that in a case- 

(a) where a return has been furnished during the period commencing on the 1st day of October, 1991 and ending on the 30th day of September, 2005 in response to a notice served under this section, and 

(b) subsequently a notice has been served under sub-section (2) of section 143 after the expiry of twelve months specified in the proviso to sub-section (2) of section 143, as it stood immediately before the amendment of said sub-section by the Finance Act, 2002 (20 of 2002) but before the expiry of the time limit for making the assessment, re-assessment or recomputation as specified in sub-section (2) of section 153, every such notice referred to in this clause shall be deemed to be a valid notice: 

Provided further that in a case- 

(a) where a return has been furnished during the period commencing on the 1st day of October, 1991 and ending on the 30th day of September, 2005, in response to a notice served under this section, and 

(b) subsequently a notice has been served under clause (ii) of sub-section (2) of section 143 after the expiry of twelve months specified in the proviso to clause (ii) of sub-section (2) of section 143, but before the expiry of the time limit for making the assessment, reassessment or recomputation as specified in sub-section (2) of section 153, every such notice referred to in this clause shall be deemed to be a valid notice. 

Explanation.-For the removal of doubts, it is hereby declared that nothing contained in the first proviso or the second proviso shall apply to any return which has been furnished on or after the 1st day of October, 2005 in response to a notice served under this section. 

(2) The Assessing Officer shall, before issuing any notice under this section, record his reasons for doing so.