Power of ITAT in case of an expense which has attained finality in earlier assessment.

I had the following situation
The assessee filed a return of income for AY 2013-14 declaring income of Rs. 20 lakhs . the A.O u/s 143(3) made on 31/12/2015 disallowed expense ‘A’ of Rs. 15 lakhs, although the supreme court has held in some other case that expense ‘A’ is allowable. The A.O assessed the income at 35 lakhs u/s 143(3). The assessee does not file for any appeal/revision application u/s 264/ rectification (i.e availed no remedies) and the time for filing the appeal/revision/ rectification have all expired.
Later A.O finds an income escaping assessment of Rs. 25 lakhs for assessment year 2013-14 based on new evidence as on 31/12/2020 and issued notice u/s 148 to the assess the escaped income of Rs. 25 Lakhs. The A.O assessed income of Rs. 60 lakhs u/s 147. The assessee filed the appeal against the order in CIT(appeals) and subsequently to ITAT.
During the proceeding in ITAT against the order u/s 147 the assessee also claimed the deduction in respect the expense ‘A’ wrongly disallowed earlier. Can the assessee be allowed to claim such deduction??