Where a pension becomes payable to or in relation to a prescribed employee, each payment that is required by section 33 to be made by the Commonwealth to the Fund in respect of that prescribed employee shall be increased by such amount (if any) as the Board determines to be necessary by reason of the prescribed employee:
(a) having contributed to the Fund at rates less than those at which, but for this Part, he would have been required to contribute; or
(b) being deemed to be a contributor to the Fund in respect of any units of pension by virtue of paragraph (b) of subsection (3) of section 100C.