815. A member institution in computing its income for a taxation year may deduct the following amounts:(a) any premium or assessment referred to in the second paragraph of section 808 which is paid or payable by it in the year, to the extent that it was not deducted by it in computing its income for a preceding taxation year;
(b) any amount repaid by the member institution in the year to a deposit insurance corporation on account of an amount described in subparagraph a or b of the first paragraph of section 814 that was received in a preceding taxation year, to the extent that it was not excluded from the member institution’s income by reason of section 815.1 for the preceding year.