Held that in view of the finding by the Tribunal that no reply was given by the assessee to explain the differential amount, it could not be said that the additions were merely estimated additions. The additional income was surrendered by the assessee, a part of which was admitted in the return of income whereas a part thereof was not. The Assessing Officer added the differential to the income of the assessee and finally, the additions to the extent for which reply could not be furnished by the assessee, were confirmed. Therefore, this was not merely an estimated addition.  That the penalty order was based on the findings rendered by the Tribunal in quantum appeal. The differential so added to the income of the assessee would be undisclosed income within the meaning of section 271AAB. The assessee’s case would squarely fall within clause (c) of section 271AAB(1) since the admission made by the assessee was not honoured in the return of income and clauses (a) and (b) would have no application in such a case.  That adequate opportunity of hearing was given to the assessee to assail the penalty as required by the provisions of section 274(1) of the Act. Whether it was through statutory notice or a non-statutory notice would be immaterial. The only requirement was that opportunity of hearing should be given specifically mentioning the ground which the assessee has to meet. That had been done in the present case. That the limb under which penalty was to be levied was clearly spelt out and the assessee could not offer any explanation against the addition. That the Tribunal having passed order in quantum appeal on September 27, 2019, the penalty order passed on March 23, 2020 was well within the prescribed time limits under section 275(1). That the facts on record did not show any such violation of principles of natural justice as pleaded by the assessee. Adequate opportunity of hearing had already been afforded to the assessee.(AY.2015-16)