I got a roll off straight truck that is 35 feet long with 3 axels. 1st to 2ed axel is 21 feet. 4 feet axel 2 to axel 3. Total of 25 feet from axel 1 to axel 3. The truck is registered for 66k. Every rental company has them at 66k. Bridge formula say 54k. How is this the case? Is there an exception or am i reading it all wrong?