In the formula in the first paragraph,(a) A is an amount equal to the amount by which the aggregate of all amounts each of which is an amount deducted by the corporation for a taxation year preceding the association year under section 776.1.38, or under section 776.1.39 in respect of the unused portion of the tax credit of the corporation for a taxation year preceding the association year, exceeds the aggregate of all amounts each of which is the maximum amount that the corporation could have deducted under section 776.1.38 for a taxation year preceding the association year if it had had sufficient tax payable under Part I for that preceding taxation year and if no reference were made to any eligible investment of the corporation in a corporation with which it becomes associated, under circumstances described in the first paragraph, at any time in the association year nor to any amount paid in connection with the eligible investment for the acquisition of a share referred to in the first paragraph of section 1129.27.28; and
(b) B is the aggregate of all amounts each of which is a balance of the special tax account payable in relation to an authorized investment certificate referred to in the first paragraph at the end of the association year, to the extent that the balance does not exceed the portion of the amount determined under subparagraph a that may reasonably be considered to be attributable to the certificate.