you are not missing anything, its just how they sell more. They try and skirt the issue because companies do not want to have to have cdl drivers and all the extra expense with that so they try and pull the wool over our eyes and do not have any real word experience with these trucks. As you said once you put the welder, some tanks. your two guys, all the tools we use everyday, hardware you will be overweight not to mention if you want to carry a sign on it or even pull a trailer, that truck needs to be on a 33k chassis.
P.S in reference to this, what happens when you are overweight? do they give you a fine and you drive away or do they make you offload until you are underweight and write a ticket?
"We currently have one of our fleet cranes with a similar setup and our drivers get popped for being overweight all the time at weigh stations. "