(1) Tax or provisional tax assessed in accordance with section 16 of this Law shall subject to section 23 be payable at the place stated in the notice of assessment, given under the provisions of section 18(2) of this Law, within thirty days after the service of such notice.

(2) The Commissioner may where good cause is shown extend the period within which such tax or provisional tax shall be paid under the provisions of subsection (1) of this section to such period as he may deem fit.