Penalty waiver procedure restored for pre-amendment assessments, limiting power to Commissioner with senior officer approval. New sub-section (7) to section 273A provides that pre-1989 versions of sub-section (1), (2) and where applicable (4) govern reduction or waiver of penalty or interest for assessments for the assessment year commencing 1 April 1988 or earlier, with the modification that the power under the former sub-section (1) is exercisable only by the Commissioner and requires the previous approval of the Chief Commissioner or Director General instead of the Board.