a. (1) A disability beneficiary who has been or shall be reinstated to active service, as provided in section 13-171 of this chapter, at a compensation not less than the final compensation on the basis of which he or she was retired, shall from the date of such restoration again become a member of the retirement system.
(2) His or her retirement allowance shall thereupon be suspended, and, subject to the provisions of paragraph three of this subdivision a, he or she shall contribute to such system thereafter in the same manner and at the same rate as he or she paid prior to his or her disability retirement, subject to the provisions of section 13-152 of this chapter.
(3) In any case where any such beneficiary reinstated under the circumstances specified in paragraph one of this subdivision a, is reinstated as a transit twenty-year plan member (as defined in subdivision sixty-one of section 13-101 of this chapter) and he or she is relieved, pursuant to subdivision l of section 13-161 of this chapter, of making contributions, such member shall not be required to make contributions so long as he or she is entitled, under such subdivision l, to be relieved of making contributions.
b. A disability beneficiary who has been or shall be reinstated to active service as provided in section 13-171 of this chapter at a compensation less than the final compensation on the basis of which he or she was retired, or who has been otherwise re-employed in city-service at such a lesser compensation, may at his or her election again become a member of the retirement system, provided he or she waives the right to receive any disability retirement allowance during the entire period of such resumed membership.
c. When any disability beneficiary has again become a member of the retirement system pursuant to the provisions of subdivision a or b of this section, any prior-service and member-service on the basis of which his or her service was computed at the time of his or her retirement shall be restored to full force and effect, and, in addition, upon his or her subsequent retirement, he or she shall be credited with all of his or her service as a member subsequent to his or her last restoration to membership.