In this appeal by revenue correctness of decision of Commissioner (Appeals) in cancelling order under section 154 of Income-tax Act, 1961 (' Act ') passed by ITO has been questioned. 2. facts in this regard are briefly following: In assessment for this year, completed on 27-11-1981, interest under section 139(8) of Act for late submission of return of income, was charged in sum of Rs. 18,032 after giving due credit for advance tax paid. Later, ITO noticed that assessee had filed advance tax estimate on 24-8-1979, that is, very much later than due date for submission of such estimate, and, therefore, tax paid in pursuance of same should not have been treated as advance tax and credit given in respect thereof, while charging interest under section 139(8). As, according to ITO, advance tax estimate filed on 24-8-1979 was invalid estimate, interest under section 139(8) should have been calculated without taking into account tax paid in pursuance of said estimate and he, therefore, rectified his earlier order under section 154 with view to enhancing interest under section 139(8) to Rs. 64,240. According to him, interest under section 139(8) levied originally in sum of Rs. 18,032 was mistake apparent from record and, therefore, same was rectifiable under section 154. 3. On appeal, Commissioner (Appeals) cancelled order holding that ITO was ' not legally justified in resorting to section 154 to cover up his earlier omission to levy interest under section 139(8) in original assessment '. He derived support for this view from decision in Chandra Metal Co. v. CIT  119 ITR 279 (All.). Being aggrieved with this order, department is in appeal before us. 4. department's contention is based on proposition that original levy of interest under section 139(8) by ITO, treating tax paid by assessee as advance tax, amounted to short levy in this behalf, inasmuch as tax paid by assessee in pursuance or invalid estimate should not have been treated as advance tax and credit given therefor while calculating interest chargeable under section 139(8) and since this was mistake apparent from record, ITO was well within his rights to rectify such mistake under section 154, as soon as same came to his notice. In fact, in grounds of appeal also and particularly so in ground No. 3 department's contention is that Commissioner (Appeals) had failed to appreciate that interest under section 139(8) was in fact levied by ITO in original assessment and, therefore, subsequent order of ITO under section 154 charging higher amount of interest was passed only with view to rectifying mistake in calculation of said interest under section 139(8) in original order, which was apparent from record. It was submitted on behalf of department, that tax paid in pursuance of invalid estimate should not have been treated as advance tax and by treating same as advance tax in original assessment, ITO had wrongly given credit for it while calculating interest under section 139(8). It was urged that this being mistake apparent from record, there was no bar against its rectification under section 154 when ITO actually found out mistake. cancellation of order of ITO by Commissioner (Appeals) was supported on behalf of assessee. 5. We are in agreement with Commissioner (Appeals) on cancellation of ITO's order passed under section 154, though for different reasons. Commissioner (Appeals) appears to have proceeded on basis that originally, ITO had failed to charge interest under section 139(8) and, therefore, he was precluded from charging same, by having recourse to provisions of section 154 following decision in S.A.L. Narayan Row v. Ishwarlal Bhagwandas  57 ITR 149 (SC). In fact, he seems to have relied on decision in Chandra Metal Co.'s case, in which facts were entirely different. In that case, interest was charged originally in wrong sum due to mistake in calculation and same was sought to be rectified under section 154 with view to charging correct amount of interest. High Court held, that original mistake was due to computational error and, therefore, it could not be held that ITO had earlier exercised his power to waive or reduce interest conferred under rules. It is not clear how Commissioner (Appeals) has referred to this decision, while, however, cancelling order under section 154, though rightly. In present case interest had been charged under section 139(8) after treating certain taxes paid by assessee as advance tax in pursuance of estimate filed by it. Later, however, ITO came to conclusion that estimate filed by assessee was invalid estimate, since it was not filed within time, and, therefore, tax paid in pursuance of same, did not amount to advance tax and, accordingly, same should not have been taken into account while calculating interest leviable under section 139(8) as per provisions of section. It is not as if that tax paid in pursuance of estimate filed on 24-8-1979 had been refunded to assessee treating it as something other than advance tax. To all intents and purposes same has been adjusted against tax due from assessee on completion of assessment, according it same treatment as would have been accorded to any normal payment of advance tax. Since there can be more than one opinion as to whether tax paid in pursuance of estimate filed beyond due date should be treated as advance tax or otherwise, we are of opinion that decision on such debatable issue of law would not be available for rectification under section 154---T.S. Balaram, ITO v. Volkart Bros.  82 ITR 50 (SC). In present case, it is not simple matter of correcting earlier arithmetical calculation error. Originally, certain amount paid by assessee was treated as advance tax and, therefore, correspondingly interest chargeable under section 139(8) was levied at lower figure after taking tax paid into account. However, subsequently ITO changed his mind and came to conclusion that tax paid in pursuance of estimate filed beyond due date should not have been treated as advance tax payment and, therefore, interest leviable under section 139(8) should be charged at higher figure without giving credit for such tax paid. question whether tax paid in pursuance of estimate filed on 24-8-1979 should have been accorded treatment of advance tax or otherwise, is debatable and therefore, it is not available to ITO to rectify earlier mistake made in this regard as if it was apparent from record. We are also fortified in coming to this decision with reference to order of this Bench in IT Appeal Nos. 595 and 596 (Bang.) of 1982 dated 14-2- 1984 in which it was held that interest allowed to assessee under section 214 of Act in higher sum could not be later rectified so as to reduce same, treating same, as if it was mistake apparent from record in view of difference of opinion amongst Courts as to date up to which such interest could be granted. 6. Having due regard to above considerations, we uphold order of Commissioner (Appeals) cancelling ITO's order passed under section 154, though for different reasons. *** INCOME TAX OFFICER v. BANGALORE ANIMAL FOOD CORPORATION LTD.