62B. In making any assessment for the year beginning on the first day of July, 1995, the 'income year' shall be deemed to include the period, if any comprised in the 'income year' as defined in the repealed clause (b) of sub-section (26) of section 2, for which the assessment would have been made if the said clause had not been repealed and where such income year exceeds a period of twelve months, the total income and the tax payable shall be prorated on the basis of the average income of a period of twelve months.