He may in cases falling under clause (a) at any time within eight years and in cases falling under clause (b) at any time within four years of the end of that year, serve on the assessee, or, if the assessee is a company, on the principal officer thereof, a notice containing all or any of the requirements which may be included in a notice under sub section (2) of section 22 and may proceed to assess or reassess such income, profits or gains or recompute the loss or depreciation allowance; and the provisions of this Act shall, so far as may be, apply accordingly as if the notice were a notice issued under that sub section: Provided that (i) the Income tax Officer shall not issue a notice under this subsection, unless he has recorded his reasons for doing so and the Commissioner is satisfied on such reasons recorded that it is a fit case for the issue of such notice; (ii) the tax shall be chargeable at the rate at which it would have been charged had the income, profits or gains not escaped assessment or full assessment, as the case may be; and (iii) where the assessment made or to be made is an assessment made or to be made on a person deemed to be the agent of a non resident person under section 43, this sub section shall have effect as if for the periods of eight years and four years a period of one year was substituted.