An enrollment of a fleet in the fleet registration plan shall be terminated by the department in the event:

(1) The department determines on the basis of an audit that fees for registration and licensing are not paid as required for 20 percent or more of the vehicles in any class of vehicles in the fleet or of those vehicles of the fleet registered in a county;

(2) The department determines on the basis of an audit that fees for registration and licensing are not paid as required for 5 percent or more of the total vehicles in the fleet;

(3) Of the conviction of the fleet registrant for any unlawful use of any license plate issued for a fleet vehicle;

(4) Of the failure of the fleet registrant to pay ad valorem taxes as required for any fleet vehicle;

(5) Of the failure of the fleet registrant to pay enrollment fees as required; or

(6) Of the forfeiture of the surety bond required under Code Section 40-2-52 or 40-2-53.