89.     Appointment of day for payment of tax and interest on overdue payments

(1)     ……….

(2)     If the taxpayer fails to pay any tax in full within the period for payment notified by the Commissioner in the notice of assessment or within the period for payment prescribed by this Act, as the case may be, interest shall, unless the Commissioner having regard to the circumstances of the case grants an extension of such period and otherwise directs, be paid by the taxpayer at the prescribed rate on the outstanding balance of such tax in respect of each completed month (reckoned from the date for payment specified in the notice of assessment or the date on which the tax has become payable in terms of this Act, as the case may be) during which any portion of the tax has remained unpaid.

(3)     ……….