Sec. 4. Except as provided in section 7 of this chapter, the fee to register a farm vehicle that is:
(1) a truck; or
(2) a tractor used with a semitrailer;
with a declared gross weight of more than eleven thousand (11,000) pounds is fifty percent (50%) of the fee listed in IC 9-18.1-5-9 for a vehicle of the same declared gross weight.