(a) A certificate to practice respiratory care must be renewed biennially.
(b) The advisory board by rule may adopt a system under which certificates expire on various dates during the year. For the year in which the certificate expiration date is changed, the advisory board shall prorate certificate fees on a monthly basis so that each certificate holder pays only that portion of the certificate fee that is allocable to the number of months during which the certificate is valid. On renewal of the certificate on the new expiration date, the total certificate renewal fee is payable.