The clauses relevant prescribing the period within which notice may be issued read as follows: (1) (a) If x x x (b) x x x 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, x x x 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 re assess such income, profits or gains or recompute the loss or depreciation allowance; x x x Provided that (i) x x x (ii) x x x (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 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.