1. Notwithstanding other provisions of this chapter, commencing January 1, 1974, commercial motor vehicles to be licensed for twelve thousand pounds or less shall be registered on a monthly series basis in the manner provided for motor vehicles other than commercial motor vehicles.

2. During the time necessary to change over from the present system of annual calendar year registration to the monthly series system, all commercial motor vehicles to be licensed for twelve thousand pounds or less shall be registered for one of twelve registration periods, which shall vary in length from a minimum of six consecutive calendar months to a maximum of seventeen calendar months. In the order of the receipt of applications for registration for the vehicles by the owners thereof, the director shall allocate to each of the twelve registration periods the number of the vehicles that will in his judgment distribute as uniformly as practicable the clerical work of registering the vehicles throughout the twelve-month period in which registration shall expire and come up for renewal. Each period shall commence January 1, 1974. The first period shall expire June 30, 1974; the second, July 31, 1974; the third, August 31, 1974; the fourth, September 30, 1974; the fifth, October 31, 1974; the sixth, November 30, 1974; the seventh, December 31, 1974; the eighth, January 31, 1975; the ninth, February 28, 1975; the tenth, March 31, 1975; the eleventh, April 30, 1975; the twelfth, May 31, 1975. Upon the expiration of the initial registration period, the vehicles so registered shall thereafter be registered for twelve-month periods.

3. The fees for registrations of such vehicles may be prorated and the prorated fee shall be paid in the manner provided in section 301.030. Applications for pro rata registration shall be made at the time and in the manner prescribed by the director of revenue.