(1) In sections 93, 100 and 129, but not in any other section of this Act, tax includes an instalment of tax payable under this Division.
(2) In sections 100 and 129, but not in any other section of this Act, tax includes additional tax payable under subsection 112(4).
(3) The ascertainment of the notional tax amount, or the amount of any instalment of tax, in accordance with this Division shall not be deemed to be an assessment within the meaning of any of the provisions of this Act.