For renewal of a license issued under this subdivision, each licensee shall participate in a program of continuing education to insure continuing professional competence. Licensees shall complete in each 2-year renewal period a minimum of 6 continuing education units in approved evaluator courses for license renewal. The requirements established by the board shall specify any reasonable approach to meeting this requirement, including but not limited to, the setting of hours, the setting of fees, and the conducting of random audits of licensees.