An employee shall receive credit during any period of duty disability and beginning September 1, 1969 during any period of ordinary disability for which benefits are paid of any amount representing the contributions that would have been made under Section 13-502 had the employee been in active service and in receipt of salary during such period. The employee shall also receive credit for District contributions during such period. Credit as service for the various purposes of this Article shall be granted the employee during the period of disability for which benefits have been paid as hereinbefore provided for in this Section.