16. If the amount paid to the spouse comes from an entitlement to a refund of contributions or to a deferred-payment pension, the amount of the refund to which the council member or former council member is entitled or, where applicable, the sum of the amounts serving to determine his pension is reduced by the sums awarded to the spouse at the date of assessment with interest compounded annually at a rate determined for each period under the Regulation respecting interest applicable under the general retirement plan for the mayors and councillors of municipalities (chapter R-16, r. 1) and accrued from 1 July of the year of assessment to the first day of the month during which the refund is issued or, where applicable, to the first day of the month during which the pension becomes payable.