15. Any withdrawal contemplated in section 14 shall not exceed, for an allowable expenditure in respect of which a certificate is issued, the lesser of the following amounts:(a) 25 per cent of such allowable expenditure, when the certificate is issued before 11 March 1981, or 50 per cent of the allowable expenditure, when the certificate is issued after 10 March 1981; or
(b) the balance of the sums deposited in the fund in favour of the corporation before the date of the withdrawal.