Rule 14. Any assessing, Appellate or revising authority may, at any time within four years from the date of any order passed by him, rectify any clerical or arithmetical mistake apparent from the record:

Provided that no such rectification which has the effect of enhancing an assessment or any penalty shall be made unless the assessing or appellate authority has given notice to the dealer of his intention to do so, and has allowed him a reasonable opportunity of being heard.