23. For the purposes of sections 20 and 22, the amount of pension or pension credit that would be obtained on the basis of the sums awarded to the spouse at the date of assessment must be established at that date according to the actuarial method and assumptions provided for in section 10. That amount is presumed applicable on the date of the member’s or former member’s 60th birthday.
If the date on which the annual retirement pension becomes payable occurs before the date on which the amount of pension obtained pursuant to the first paragraph is presumed applicable or if the retirement pension is being paid on the date of payment and the latter date occurs before the date on which that amount of pension is presumed applicable, that amount of pension must be reduced by 0.50% per month, calculated for each month between the date on which it begins to apply and the date on which it is presumed applicable, without exceeding 65%. The foregoing also applies to the amount of pension credit.
If the retired member retired before the date of payment and if that date occurs after the date on which the amount of pension obtained pursuant to the first paragraph is presumed applicable, that amount of pension must be increased by 0.50% per month, calculated for each month between the date on which it is presumed applicable and the date on which it begins to apply if the retired member retired before the date on which that amount of pension is presumed to apply, or for each month between the date on which the retired member retired and the date on which that amount of pension begins to apply, if the retired member retired on the date on which that amount of pension is presumed applicable or thereafter.