70.1. The provisions of a pension plan that, where such provisions were in effect on 4 June 1997, allowed a member or spouse who had become entitled to a pension to choose, before it comes into payment, to replace it, in whole or in part, by a pension of which the amount is changed in accordance with the Act in order to take into account an amount similar to the benefits determined under the Old Age Security Act (R.S.C. 1985, c. O-9), the Act respecting the Québec Pension Plan (chapter R-9) or a similar plan within the meaning of subparagraph u of section 1 of that Act, continue to apply with respect to any person who was a member of the plan on the date mentioned hereinabove and to that member’s spouse.