Interim Board powers to exercise Settlement Commission functions apply mutatis mutandis with retrospective effect under income tax law. An inserted sub section provides that the power of the Settlement Commission shall be exercised by the Interim Board and that the provisions applicable to the Settlement Commission shall apply mutatis mutandis to the Interim Board, with the insertion deemed effective from the 1st day of February, 2021; related clauses apply the same mechanism to other settlement provisions so that the Interim Board assumes the Commission's functions and powers from that date.