(1) A reduced incentive payment shall be made to any county having in its employ a qualified county highway superintendent for only a portion of the calendar year preceding the year in which the payment is made. Such reduced payment shall be in the proportion of the amounts listed in section 39-2503 as the number of full months such a qualified person was employed is of twelve.
(2) Any county that contracts with a consulting engineer or engineering firm to perform the duties outlined in section 39-2502 rather than employing a qualified county highway superintendent shall be entitled to an incentive payment equal to two-thirds the amount provided in section 39-2503.
(3) Any county that contracts with another county or with any city or village for the employment of a qualified highway superintendent as provided in section 39-2114, shall be entitled to the incentive payment provided in section 39-2503 or the reduced incentive payment provided in subsection
(1) of this section.