(1) On new registrations of automobiles, trucks and truck tractors, the excise tax payment must be made prior to registration and is for a one-year period from the date of registration.

(2) Vehicles registered under the International Registration Plan are subject to an excise tax determined on a monthly proration basis if their registration period is less than 12 months.

(3) For commercial vehicles manufactured in model year 1996 and after, the amount of excise tax due for trucks or truck tractors registered for more than 26,000 pounds and for Class A special mobile equipment, as defined in Title 29-A, section 101, subsection 70, is based on the purchase price in the original year of title rather than on the list price. Verification of purchase price for the application of excise tax is determined by the initial bill of sale or the state sales tax document provided at point of purchase. The initial bill of sale is that issued by the dealer to the initial purchaser of a new vehicle.