(1) A teacher employed full time by any institution of public education, including higher education, may be employed and paid by the same or another institution for additional part-time work outside the teacher's regular hours, not to exceed fifteen (15) clock hours beyond the teacher's regular employment per week and not to exceed four hundred (400) clock hours out of any nine-month period.
(2) If the additional part-time work is or includes teaching in an institution of higher education, the teacher shall be limited to teaching no more than two (2) courses per quarter or semester.
(3) The employment must be approved by the governing board of each institution of public education.