These three appeals involve very ticklish issue. Assessee in this case filed three returns in names of three registered firms on 3rd Sept., 1975 as under: M/s Shiv Kumar Bishnoi (10) Partners Rs. 12000 (loss) M/s Shiv Kumar Bishnoi (11) Partners Rs. 5000 (loss) M/s Shiv Kumar Bishnoi (12) Partners Rs. 24854 (loss) On 30th March, 1976 assessee filed revised returns as under: M/s Shiv Kumar Bishnoi (10) Partners Rs. 8410 (Loss) M/s Shiv Kumar Bishnoi (11) Partners Rs. 2710 (Loss) M/s Shiv Kumar Bishnoi (12) Partners Rs. Nil ITO completed assessments which were appealed against and matter rested there. Latter assessee made applications to ITO that original returns were filed in pursuance of s. 139(4) of IT Act and time limit for completion of assessment had expired on 2nd Sept., 1976. ITO had actually completed assessments on 23rd Feb., 1977, 24th Feb., 1977 and 28th March, 1977. extended time limit for revised return was not available in case where return had been filed under s. 139(4). Reference was made to Circular No. 888 dt. 1st Oct., 1975 which had clarified position. Board's instructions were binding on ITO and assessment in this case was not completed in accordance with those instructions. Reference was made to case of Navnit Lal Javeri vs. K.K. Sen (1965) 56 ITR 198 (SC) about binding nature of these instructions and it was contended that it was pure mistake of law apparent on face of record. assessment orders should, therefore, be rectified. ITO rejected these applications on ground that issue involved was of contentious nature and was not covered by s. 154. said conclusion has been endorsed by AAC on appeal filed by assessee. assessee has come up in second appeal before us. We have heard representatives of parties at length in there appeals. main reliance of assessee was upon Circular of Board referred to above wherein Board had sought advice of Law Ministry in file no. 201/20(74-IT(A.II) which was to effect that right to file revised return is concession given only to those who have filed return under s. 139(1) or 139(2). Sub-s. (4) of s. 139 does not contemplate filing of more than one return. Reliance was also placed upon decision of Rajasthan High Court in IT Ref. No. 8/1978 since reported in case of Smt. Sobha Rani vs. CIT (1985) 49 CTR (Raj) 53 decided on 11th Jan., 1985 wherein their Lordships have taken view in favour of assessee. After carefully considering all facts and circumstances of case, we are afraid, we are not inclined to interfere with conclusion of authorities below. issue in dispute is certainly contentious. Though this bench had taken view in favour of assessee it was not without great deal of hesitation and reluctance that dictating member had accepted that conclusion. reason for that is plain and simple language of s. 153. According to sub-s. (1), no order of assessment shall be made under s. 143 or 144 at any time after (a) xxx xxx xxx (b) xxx xxx xxx (c) expiry of one year from date of filing of return or revised return under sub-section (4) or subsection (5) of sec. 139 whichever is latest. Bench's decision was following decision of Special Bench in ITO vs. Bohra Films & Finance (1983) 34 CTR (Trib) 123 (Jp): (1983) 4 ITD 247 (Jp) (SB). fact that matter had to be referred to Special Bench itself shows that issue is quite contentious. In fact there is direct decision of Calcutta High Court in case of Kumar Jagdish Chandra Sinha vs. CIT (1982) 26 CTR (Cal) 323: (1982) 137 ITR 722 (Cal) which decides issue clearly in favour of Department. In any case following observations of Special Bench at pages 261 to 262 are very relevant and clinch entire issue: "However, we do not want to dilate on this aspect as that is not question directly before us though perhaps authorities do support view that successive revised returns under s. 139(5) can be filed. Then other question that arose is whether return filed under s. 139(4) can be corrected and another return under s. 139(4) be filed. There may be two views on this. No doubt Calcutta High Court has stated that even return under s. 139(4) can be corrected under s. 139(5) but since we do not want to adopt that view, we proceed to discuss this aspect on basis that return under s. 139(4) cannot be revised under s. 139(5). All same whether another return under s. 139(4) again can be filed or not is question. This is where we want to say that there can be possibly two views One view is that there can be successive returns filed under s. 139(4) but subject to limit prescribed under s. 153 for completing assessment. This view is fully supported by observations of Delhi High Court in Malhotra's case (supra). Now take for instance this very case. assessee could file another return under s. 139(4) as long as period for completing assessment under s. 153 is not completed. other view may be that so far as return under s. 139(4) is concerned, there can be no subsequent return under s. 139(4). To hold that there should not be any subsequent return under s. 139(4) even within period of limitation is not warranted by scheme of Act. If such view is taken it will lead to practical difficulties. If assessee, who has filed return under s. 139(4) finds obvious mistake or omission which is not intended cannot correct it by filing another return under s. 139(4) within period prescribed. We do not think that legislature intended such situation to arise. It is therefore, proper to hold that successive returns under s. 139(4) can be filed so long as they are ultimately within prescribed time." disputed year in present case is 1973-74. Therefore, return under s. 139(4) could be filed upto 31st March, 1976. Such return would be within limitation. return was actually filed on 30th March, 1976. In accordance with Special Bench decision, it may not be called revised return but was certainly successive return. Special Bench was, of view that as long as there is limitation for filing return under s. 139(4) assessee may file as many returns as he thinks fit. Only when limitation has expired, any revised return filed by him would be invalid for purpose of extending period of limitation. In fact following decision of Special Bench, dictating member took contrary decision in favour of Department in ITA No. 792/JP/84 decided on 24th Sept., 1985. So far as Rajasthan High Court decision is concerned, in that case assessment year involved was 1970-71. Therefore, return under s. 139(4) could be filed latest by 31st March, 1973. actual returns were filed on 2nd March, 1971, 12th Oct., 1972, 7th Dec., 1972 and 5th Dec., 1973. It is obviously that last revised return was invalid, since on that day no return under s. 139(4) could at all be filed. assessment in this case was made more than one year after last valid return dt. 7th Dec., 1972 was filed. Thus Rajasthan High Court decision would not straight way made present assessments to be time-barred. In any case matter in dispute cannot be said to be free from difficulty. Since assessee did not agitate issue in appeal before AAC, assessment should be deemed to have become final except only in relation to mistakes apparent from records. It has been held in case of Volkart Bros. vs. T.S. Balaram, ITO (1971) 82 ITR 50 (SC) that "a mistake apparent on record must be obvious and patent mistake and not something which can be established by long drawn process of reasoning on points on which there may be conceivably two opinions. decision on debatable point of law is not mistake apparent from record." present case obviously does fall in that category. Accordingly we are of opinion that no interference is called for by us at this stage. appeals fail and are hereby dismissed. A. KALYANASUNDHARAM, A.M. I concur with conclusion arrived at my ld. Brother only to extent that under rectification proceedings, issue could become arguable and therefore may not be said to be mistake apparent from record. At same time, I may also add that Supreme Court in case of CIT vs. Thayaballi Mulla Jeevaji Kapasy (1967) 66 ITR 147 (SC) had held that if notice is invalid, then all proceedings on pursuance of such invalid notice would be illegal and void, thereby even if assessee has co-operated consequent to such invalid notice, even then proceedings would remain invalid. This has been added by me only to extent that Act does not envisage any revised return for belated returns under s. 139(4) and once time of one year has been granted under that section further time of one more year under s. 139(6) is not at all permissible under law. *** SHIV KUMAR BISHNOI & ORS. v. INCOME TAX OFFICER