339.5. A taxpayer may deduct in computing his income for a taxation year an amount equal to the aggregate of the following amounts:(a) where the taxation year ends before 1 January 1991, the aggregate of all amounts each of which is that portion of an amount paid to the taxpayer before 1 January 1991 and included in computing his income for the year or a preceding taxation year by reason of section 310, to the extent that the said section refers to Title IV of Book VII, paragraph k of section 311 or section 317, that may reasonably be considered as a refund of additional voluntary contributions made by the taxpayer before 9 October 1986 to a registered pension plan for his benefit in respect of services rendered by him before the year in which the contributions were made, to the extent that the contributions were not deducted in computing his income for any taxation year, and
(b) the least ofi. $3,500,
ii. the aggregate of all amounts each of which is an amount included after 31 December 1986 in computing his income for the year by reason of section 310, to the extent that the said section refers to Title IV of Book VII, paragraph k of section 311, paragraph c.2 of section 312 or section 317, and
iii. the balance of the annuitized voluntary contributions of the taxpayer at the end of the year.