Appointment or promotion to employment or rank shall not be deemed complete until a period of probation not to exceed six (6) months has elapsed, not necessarily continuous. Periods of any unpaid leave and periods of any paid disability leave shall not count towards completion of the term of probation. Should appointees fail to complete the promotional probationary period, they shall return to their former permanent position. (Amended November 8, 1988: amended April 21, 1941)