6. In the case provided in section 4, where the contributions paid by the person during the year of leave or part of a year of leave are less than the contributions required under the retirement plan to which he contributes in order to credit a year of service or part of a year of service for each year or part of a year during which he received only part of his salary, the difference may be paid by the person.
Failing payment of such difference, the service and the pensionable salary for the year during which the agreement becomes null or, as the case may be, the previous year for which the person received only part of his salary shall be calculated in proportion to the contributions received by Retraite Québec.
O.C. 1863-83, s. 6; O.C. 1773-86, s. 1.