(1)Where it appears to the Assistant Commissioner that a registered person chargeable with the levy has, for the relevant quarter, paid as levy an amount less than the due amount of the levy payable by him or chargeable from him for that quarter, the Assistant Commissioner may, assess such person at the additional amount at which, according to the opinion of the Assistant Commissioner, the levy ought to have been paid by such person. The Assistant Commissioner shall give such person a notice of such assessment accordingly.