12. That for the 1947 and subsequent taxation years, the provision exempting the income of certain cooperative companies and associations be repealed and that for the 1946 and subsequent taxation years provision be made that there may be deducted from a taxpayer's income the aggregate of the payments made,
(a) in the taxation year or within six months thereafter to his customers of the taxation year; and
(b) in the taxation year to his customers of a previous taxation year after the 1941 taxation year and not previously deducted under paragraph (a) in respect of specified allocations in proportion to patronage for the said years the prospect of which was held forth;
(c) by the statute or by-laws under which the taxpayer carries on business or by his contracts with his customers; or
(d) by the taxpayer in a specified manner prior to the commencement of the taxation year except that portion of such payments as woidd if deducted leave the taxpayer with an income less than an amount determined by deducting from three per cent of the capital employed in the business, including therein borowed moneys, the interest paid by the taxpayer on borrowed moneys and deductible as an expense in computing his income.