I wish those "ton" ratings would completely disappear from people vocabulary but for some reason they persist. I think it causes a lot of confusion because people think it's an actual weight rating.
The trucks really should just be classed by GVWR with the system that the DOT uses. It runs class 1 thru 8 with 1 being the lightest and 8 the heaviest. Even there, most 150 or 1500 trucks are really into class 2 now. Most 250 or 2500 trucks are into class 3 and most 350 or 3500 trucks are pushing into class 4 territory.
The only way to know what a truck will do is to look at the actual GVWR.