(a) An association's board of directors may by resolution increase assessment rates on life insurance certificates in force up to the rate on an attained age basis in accordance with the 1956 Chamberlain Reserve Table, with interest at 3-1/2 percent a year, or any other reasonable, equitable, or necessary increase. The board may also adjust assessment rates on accident, health, and hospitalization insurance certificates in force.
(b) An assessment rate increase or adjustment under this section on insurance certificates in force applies to all classes of the same or similar certificates.