17. If the amount paid to the spouse comes from an entitlement to a refund of contributions or to a deferred-payment pension and if the pension is being paid at the date of payment, or if that amount comes from an entitlement to a pension, the pension of the former council member shall be reduced, from the date of payment, by the amount of pension payable at that date that would have been obtained on the basis of the sums awarded to the spouse at the date of assessment.
For the purposes of the first paragraph, the amount of pension payable at the date of payment shall be established according to the actuarial method and assumptions provided for in section 8. That amount of pension is deemed to be payable for at least 15 years, as mentioned in section 27 of the Act, in respect of the annual pension of the former council member. Where the pension is being paid at the date of payment, that period corresponds to the residual period applicable to the annual pension at that date.