If this took place in Texas, it makes no sense. Ignoring Class M (motorcycle) licenses, Texas has Class A, B and C licenses in both commercial and non-commercial categories. The difference between driving a 3/4 and a 1 ton truck should make no difference whatsoever in regard to whether a commercial or non-commercial license is required - that's based strictly on whether or not the truck is being used for a non-excluded commercial (i. e. , for profit) venture. Strictly speaking, 1/2 ton trucks pulling landscape trailers require a commercial license, and some Harris County yard crews have found this out the hard way.
Rusty
Rusty