Harsha Devani, J.

1. By these appeals under section 260A of the Income Tax Act, 1961 (hereinafter referred to as "the Act"), the appellant - revenue has called in question the common order dated 21.08.2015 passed by the Income Tax Appellate Tribunal, Ahmedabad Bench "D", Ahmedabad (hereinafter referred to as "the Tribunal") in ITA No. 1199/Ahd/2006, by proposing the following four questions, stated to be substantial questions of law:

"[1] Whether the Income Tax Appellate Tribunal committed substantial error of law in treating the reassessment proceedings as vitiated in law, quashing reassessment order, and not deciding on the issues raised by the Revenue in appeal on the ground that the order of the A.O. stood merged with the order of C.I.T. (A), following the ratio of judgment of Hon'ble Gujarat High Court in the case of United Phosphorus Ltd. v. ACIT (2011) 56 DTR 196 (Guj) without deliberating on the issues involved on merits, when excepting the issue of gross interest for computing profit for the purpose of deduction u/s. 80HHC of the Act, none of the issues referred to in order u/s.143(3) r.w.s. 147 of the Act were subject matter of assessment u/s. 143(3) of the Act and CIT(A)'s order on assessee's appeal against order u/s. 143(3) of the Act, whereas the Hon'ble Gujarat High Court in the case of United Phosphorus Ltd. (supra) elaborated in detail as to how the A.O.'s order u/s.143(3) r.w.s. 147 of the Act got merged with order of CIT (A)?

[2] Whether the Income Tax Appellate Tribunal committed substantial error of law in treating the reassessment proceedings as vitiated in law, quashing reassessment order, ignoring that the A.O. had reason to believe that income chargeable to tax has escaped assessment, and all the issues excepting the issue of consideration of gross interest for computing profit for deduction u/s.80IA were validly reopened in accordance with the provision of section 147 of the Act, as is evident from the reasons recorded for reopening of assessment and the order disposing of assessee's objection to the issue of notice u/s. 148of the Act, and discussions on the issue involved in order u/s. 143(3) r.w.s.147 of the Act which finds support from various judicial decisions?

[3] Whether the Income Tax Appellate Tribunal committed substantial error of law in treating the reassessment proceedings as vitiated in law, quashing reassessment order, without considering that the Hon'ble Gujarat High Court vide its order dated 31/07/2002 and 06/08/2002 upheld the validity of reassessment proceedings on the issue of recalculation of deduction u/s. 80IArelating to interest on overdue bills in the assessee's case for A.Y. 1997-98 and 1999-2000, and that identical issue was involved in assessee's case for A.Y. 2000-01?

[4] Whether the Income Tax Appellate Tribunal committed substantial error of law in quashing reassessment proceedings, ignoring the fact that the assessment was reopened within 4 years from the end of relevant assessment year, which can be reopened even though there is no failure on the part of the assessee to disclose fully and truly all material facts necessary for his assessment for that year?"

2. The assessment years are 2000-01 and 2001-02. The assessee Company filed its return of income for assessment year 2000-01 on 30.11.2000 declaring total income at Rs. 15,92,260/- under section 115JA of the Act. The return was processed under section 143(1) of the Act on 09.03.2000. The assessee Company filed a revised return of income declaring total income under section 115JA of the Act at Rs. 15,92,21,250/- on 01.06.2001. The Assessing Officer finalized the assessment under section143(3) of the Act on 27.11.2002 under normal provisions determining total income at Rs. 11,84,80,295/- and computed income under section 115JA of the Act at Rs. 17,75,85,674/- after making various additions/disallowances.

3. For assessment year 2001-02, the assessee filed its original return of income on 31.10.2001 and revised retur