OK GVW and GVWR are the same thing. There is no difference between weight and weight.
The curb weight is the weight of the vehicle from the manufacture which is an 'estimate' of the weight with given options.
The problem I see is that even though one say it can and another says it can't, I don't see where the proper way to figure out the payload was used.
1 - load your van with everything you are going to use and fill up the fuel tank
2 - go get it weighed at a Cat scale or another place the ensures accurate weight.
3 - take your GVW (GVWR) and subtract the ticket weight, then subtract 200 more - that is the safe amount you can carry.
As for the DOT, a lot of DOT officers are getting ****ed at vans and hot shots and they are told not to bother the poor van owners. I know one MSP officer who put out of service one van that 2000 lb over weight that the contractor was with one of these 'top tier' carriers. He claimed it was legal to do, she said we are giving you a ticket and you will have to find another way to get it to the delivery.
Every officer interpets the laws and regulaitons differnetly but I am going to renew my call that I am really thinking that Vans should be treated like trucks, logging, inspections and running into scales.
OH and FYI, the driver has the ultimate responsiblity with their vehicle. That means if they stick 4000lbs on your van and it ends up in an accident, the insurance may not cover a dime of your problem or if you get the ticket, it's yours.
Don't forget - vans have to scale in Michigan.