31.3. The time during which a teacher is on leave without pay or ceases to hold a position contemplated by this Act in order to engage in specialized studies in accordance with the regulations made by the Government shall be counted for him for each of the years during which he is so on leave or is engaged in such studies, provided that
(1) he is authorized for such purpose by the Commission;
(2) he pays into the consolidated revenue fund, for each of those years, an amount equal to the deductions that would have been made, had he not been so on leave or not so engaged in such studies, based on the salary he was receiving when he was granted the leave or began to be engaged in those studies; and
(3) he holds a position contemplated by this plan from the end of his leave without pay or specialized studies, unless he has deceased or become disabled or entitled to retirement or unless, upon his return, he transfers to the service of an employer with whom the Commission has entered into an agreement of transferability.
The Commission shall determine the times when such payments must be made. The amount determined in the first paragraph bears interest at the rate determined by regulation of the Government if the application for authorization is made after the end of the year in which the teacher has been on leave without pay or engaged in specialized studies. The interest accrues from the expiry of the leave without pay or the end of the specialized studies.