157.13. In computing a taxpayer’s income from a business or property for a taxation year ending before the time at which a building or a part thereof acquired after 31 December 1989 by the taxpayer has become available for use by the taxpayer, there may be deducted an amount not exceeding the amount by which(a) the lesser ofi. the amount that would have been deductible under paragraph a of section 130 for the year in respect of the building if section 93.6 were not applicable, and
ii. the taxpayer’s income for the year from renting the building, computed without reference to this section and before deducting any amount in respect of the building under paragraph a of section 130, exceeds
(b) the amount deductible for the year under paragraph a of section 130 in respect of the building, computed without reference to this section.
The amount deducted under the first paragraph is deemed to be an amount deducted by the taxpayer by reason of paragraph a of section 130 in computing the taxpayer’s income for the year.