(1) Subject to such rules as may be made and for reasons to be recorded in writing, the Commissioner may, on his own motion, revise a provisional assessment under section 46 or section 48, or deemed to have been made under sub-section (1) of section 47 or order passed by a person appointed under sub-section (1) of section 6 to assist him.

(2) Notwithstanding anything contained elsewhere in the Act, where an assessment in respect of the dealer for any period is taken up under clause (c) or clause (d) of sub-section (1) of section 46, the Commissioner may, on his own motion, revise the orders of assessments under section 45,or section 46, or section 47 or section 48 for the previous five years also.