(1) Where any amount of tax becomes payable under section 76, 77, 91C(4) or 91E(4) and is not paid, simple interest on the amount shall be paid by the accountable person, and such interest shall be calculated from the date on which the amount became payable and at a rate of 0.0274 per cent for each day or part of a day during which the amount remains unpaid.

(2) Where an amount of tax is refunded to a person and -

(a) no amount of tax was properly refundable to that person under section 99(1), or

(b) the amount of tax refunded is greater than the amount properly refundable to that person under section 99(1),

then simple interest shall be paid by that person on any amount of tax refunded to that person which was not properly refundable to that person under section 99(1), from the date the refund was made, at the rate of 0.0274 per cent for each day or part of a day during which the person does not correctly account for any such amount refunded which was not properly refundable.

(3)