The salary rate for an employee promoted to a vacant position in the classified service shall be established by the Director of Human Resources Management in accordance with the Salary Plan and applicable personnel procedures; provided, however, an employee's salary rate, upon promotion, shall not be established at a rate less than the minimum rate or in excess of the highest rate within the applicable salary range. Whenever an employee returns to the employee's former position upon the completion of any promotion authorized under the provisions of Sections 16-148(a)(7)(C), 16-151(b), or 16-178, the employee's salary rate shall be reestablished by the Director of Human Resources Management as if the employee had remained in the former position.