1. Where a pension granted under the Act respecting the Civil Service Superannuation Plan (chapter R-12), after 10 years of credited service, except a pension granted to a child and those provided for in section 83 of the Act, is lower than the benefit calculated in accordance with section 2 of this Plan, a benefit, equal to the amount by which the benefit set out in section 2 exceeds that which would have been paid under the Civil Service Superannuation Plan, shall be paid.