(a) If an officer or employee works overtime in his regular position or title or in a position the title of which is allocated to the same salary grade as his regular position, he shall be compensated for work in excess of 40 hours at one and one-half times the regular hourly rate of pay.

(b) When the overtime is worked in a position allocated to a salary grade lower than the officer's or employee's regular position, he shall be compensated for work in excess of 40 hours at one and one-half times the hourly rate of pay of the maximum salary of the lower position plus such longevity increments to which he would otherwise be entitled were he in such lower grade position, but in no event in excess of one and one-half times the hourly rate of pay of his regular position.

(c) When the overtime is worked in a position which is allocated to a higher salary grade than the grade of the officer's or employee's regular position, he shall be compensated for work in excess of 40 hours at one and one-half times the hourly rate of compensation he would be entitled to if he were permanently promoted to the higher position.

(d) The hourly rate of compensation shall be determined by dividing the basic annual rate of compensation plus any additional compensation payable because of the location of employment or because work is performed between 6 p.m. and 6 a.m. by 2,000. The hourly rate of compensation for per diem employees shall be determined by dividing the per diem rate by eight.