42. Chapter III, Division III of Chapter IV and Chapter V apply to a person who has already availed himself of the Act respecting pension coverage for certain teachers (chapter P-32.1) and who is an employee within the meaning of the Act respecting the Government and Public Employees Retirement Plan (chapter R-10). Any pension credit to which the person has become entitled under sections 86, 100 and 104 of the Act respecting the Government and Public Employees Retirement Plan is cancelled. However, if the person referred to in the first paragraph died before 26 June 1986 and was 65 years of age or older at the time of his death, or if his age added to his years of service totalled 90 or more, sections 20, 24, 25 and 32 apply, in respect of the years that have entitled him to the pension credit under Division III of the Act respecting pension coverage for certain teachers, to the spouse’s pension or, as the case may be, to the guaranteed benefit, according to the election made by him under section 18 of the said Act. In that case, sections 20, 24, 25 and 32 shall apply as though they had been in force on the date on which the spouse’s pension or, as the case may be, the guaranteed benefit became payable. The maximum amount provided by section 22 shall be computed as of the same date with respect to the benefits the person would have been entitled to receive.