16.An employee ceases to qualify for membership in this plan on the day the employee holds unionizable employment within the meaning of the Act respecting the Government and Public Employees Retirement Plan (chapter R-10) if the employee begins to hold unionizable employment more than 180 days after the date on which this plan ceased to apply to the employee. The employee shall be a member of the Government and Public Employees Retirement Plan from that day, subject to the first paragraph of section 3.1 of that Act.