(4) Where, as a result of an order under section 154 or section 155 or section 250 or section 254 or section 260 or section 262 or section 263 or section 264 or an order of the Settlement Commission under subsection (4) of section 245D, 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 and the 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.