(4)Where, as a result of an order under section 15 or section 17 of this Act or section 254 or section 260 or section 262 of the Income-tax Act as applicable to this Act by virtue of section 21 of this Act, the amount on which interest was payable under sub-section (1) or sub-section (3) has been increased or reduced, as the case may be, the interest shall be increased or reduced accordingly, and -(i)in a case where the interest is increased, the Assessing Officer shall serve on the assessee a notice of demand in the prescribed form specifying the sum payable and such notice of demand shall be deemed to be a notice under section 156 of the Income-tax Act as applicable to this Act by virtue of section 21 of this Act, and provisions of this Act shall apply accordingly;(ii)in a case where the interest is reduced, the excess interest paid, if any, shall be refunded.
