Closest to 5% Rule. The salary of an employee who advances from one grade to a higher grade shall be the increment nearest the salary last received by such employee in the lower classification plus 5%. Thereafter, the employee shall be advanced in accordance with Section 9.02 of this article. An employee who voluntarily demotes to their previously held position within twelve (12) calendar months following promotion shall be returned to the same pay step which was applicable immediately prior to the promotion. The provisions of this subdivision shall also be applicable whenever an employee is detailed to perform all or substantially all of the duties of a higher paid classification. However, a detailed employee will only receive advancement to a higher step based upon their permanently certified title.