(4)The deduction specified in sub-section (1) shall be allowed in computing the total income in respect of each of the ten assessment years beginning with the assessment year relevant to the previous year in which the industrial undertaking begins to manufacture or produce articles or the business of the hotel starts functioning:Provided that,-(i)in the case of an industrial undertaking which has begun to manufacture or produce articles, and(ii)in the case of the business of a hotel which has started functioning, after the 31st day of December, 1970, but before the 1st day of April, 1973, this sub-section shall have effect as if the reference to ten assessment years were a reference to ten assessment years as reduced by the number of assessment years which expired before the 1st day of April, 1974.
