There is a slightly higher cost for commercial plates here over combination plates. But its no where near Richards numbers which in my opinion encourages dishonesty and averting the law. Here for a vehicle with a 10001-11000 gvw the registration is as follows for 12 months.
Commercial reg $137.60
Combination reg $134.60
They allow combination plates here up to 12,500 pounds so allot of the newer 350/3500s are over with the new weights of 13000 gvw. The thing that is sweet about the combination is they last 24 months and can expire when ever that 24 months is met. So any month of the entire year but the commercial reg all expire in April every year. You bought your truck in March great see you in a few weeks when its time to renew the reg. And they only pro rate the cost in 6 month increments. I got screwed on a trailer a few years back I missed 6 months and the lower rate by 3 or 4 days. So that was a nice 60-70 dollar hit but my times worth more then that so coming back later and dealing with all the lines again was not going to happen.