217.13. Subject to section 217.15, where a taxpayer carries on a business in a particular taxation year, there may be deducted in computing the taxpayer’s income for the year from the business, as a reserve in respect of income on 31 December 1995, such amount as the taxpayer claims not exceeding the least of(a) the specified percentage for the particular taxation year of the taxpayer’s income on 31 December 1995 in respect of the business;
(b) where an amount was deductible under this section in computing the taxpayer’s income for a preceding taxation year from the business, the amount included under section 217.14 in computing the taxpayer’s income for the particular taxation year from the business; and
(c) the taxpayer’s income for the particular taxation year computed before deducting any amount under this section in respect of the business or under paragraph j of section 339 or any of sections 346.1 to 346.4 and 350.1.