(1) Any calculation under these Regulations shall be made on the following assumptions -
(a) the assumption that the debtor will not be entitled to any income tax relief relating to the transaction other than relief under section 19 of the Income and Corporation Taxes Act 1970 [1970 c. 10; Section 21 was amended by 1976 c. 40, Schedule 4, paragraph 21.] and Schedule 4 to the Finance Act 1976 [1976 c. 40.] (which afford relief in respect of premiums under certain policies of insurance) without any deduction under section 21 of the said Act of 1970;
(b) the assumption that no assistance is given under the Home Purchase Assistance and Housing Corporation Guarantee Act 1978 [1978 c. 27];
(i) in the case of a transaction which provides for repayment of the credit or of the total charge for credit at or not later than a specified time or times, the assumption that the creditor will not exercise any right under the transaction to require repayment at any other time or times; and