For purposes of establishing a new fleet registrant and in order to establish a uniform month of expiration:
1. The department shall maintain the valuation for the vehicle license tax determined pursuant to section 28-5801 at the current valuation if it is necessary to calculate a partial year vehicle license tax.
2. The gross weight fee prescribed in section 28-5433 and the motor carrier fee prescribed in section 28-5854 may be discounted on a monthly basis for purposes of calculating a partial registration year.