Section 13-506. Re-entry into service

Any withdrawn contributor, who does
  not withdraw his or her contributions from the annuity savings fund,  on
  again  entering  the  membership  as  the  result  of  reappointment  or
  restoration to service, may  be  entitled  to  the  service  credit  and
  status,  including  the reserve-for-increased-take-home-pay, to which he
  or she was entitled immediately prior to his or her  withdrawal,  except
  as  provided  in section 13-556 of this chapter, provided that he or she
  returns to membership within a period of seven  school  years  following
  such  withdrawal,  and  further  provided,  that  he or she has not been
  absent from service for more than seven  school  years  during  any  ten
  consecutive  school  years  since  he or she became a contributor of the
  retirement system, and further provided that in  computing  his  or  her
  average  salary  for  retirement  purposes  only the earnable salary for
  years of actual service shall be used.
    At no time shall  this  section  be  so  construed  as  to  result  in
  depriving a contributor of credit for substitute teaching service in the
  New  York  city  public schools or for teaching service on other than an
  annual basis in the colleges under the city university of  New  York  of
  the  city of New York where such service was performed during the period
  between the contributor's withdrawal from membership  in  the  teachers'
  retirement systems and his or her re-entry into membership.