Power to rectify errors apparent on the face of the record.

(1) The Commissioner may, on his own motion or on an application made at any time within six months from the date of any order passed by him, rectify any error apparent on the face of the record: provided that no such rectification which has the effect of enhancing an assessment, shall be made unless such authority has given notice to the assessee and has allowed him a reasonable opportunity of being heard. (2) Where such rectification has the effect of reducing an assessment, the excess amount if any paid by the assessee shall be adjusted towards any tax that may accrue in future.