(1) Where at any time, it appears that any person or property has been inadvertently omitted from the assessment records or inadequately or improperly assessed relating to any tax, a clerical or arithmetical error is committed in the records, the Commissioner will assess or reassess or rectify the errors, as the case may be:
Provided that no such assessment shall be made where it has the effect of an increase in the assessment unless [Act No. 11 of 2019] 87 reasonable opportunity to show cause against the proposed action is given to the person affected.
(2) Such assessment or reassessment or correction of records shall not relate to a period earlier than five and half years immediately preceding the current half-year.