Deemed sale of leasehold rights: transfer treated as land disposal and gratuity disallowance subject to recomputation. An Explanation deems transfer of a leasehold or other right of occupancy as a sale or transfer of the land; where gratuity provisions disallowed for non-compliance are later complied with, the original disallowance is to be treated as wrongly made and the tax officer must recompute and amend the assessment under the correction procedure with the specified four-year reckoning period; additional consequential amendments add a newly numbered clause and insert a newly referenced exemption provision into specified sections effective from the stated commencement date.