(1) Subject to section 22H, a contributor who has made an election in accordance with the last preceding section and becomes eligible or is required to contribute for an additional unit or units of pension in pursuance of this Act may, within the prescribed time, elect to contribute for that additional unit, or those additional units, at the appropriate rate based on a retiring age of sixty - five years.
(2) A contributor who:
(a) has made an election to contribute at rates based on a retiring age of sixty years;
(b) has attained that age but has not attained the age of sixty - five years;
(c) but for subsection (4) of section 20, would have been eligible or required to contribute for an additional unit of pension;
may, within the prescribed time, elect to contribute for that additional unit at the appropriate rate based on a retiring age of sixty - five years.
(3) Where a contributor has made an election under subsection (1) or (2):
(a) any further additional unit of pension for which he commences to contribute after that election shall be at the appropriate rate based on a retiring age of sixty - five years; and
(b) the maximum age for retirement of that contributor shall, in respect of all the additional units of pension in relation to which this section applies, be sixty - five years.
(4) Any additional contribution payable by reason of an election under subsection (2) is payable as from the date of the election.
(5) A person is not entitled to make an election under this section after 30 June 1976.