Institutions of higher education shall be exempt from the provisions of § 19-4-1707 [repealed] to the extent that they shall be allowed to hire adjunct professors and visiting professors who are currently providing professional and consulting services to the State of Arkansas, providing that they are not in a position to influence decisions regarding the awarding of grants or contracts, and providing that the term of their employment with the institution of higher education does not exceed twenty-five percent (25%) of that required for a full-time employee.