I think we went through this a few days ago,
so here is it again.
THE only weight you need to worry about it the weight on the sticker. If it says GVRW is 8660, then that is the absolute amount of weight you can legally carry.
THE DOT 10,000 or less rule has to do with classifying the vehicle and used as a threshold to more intense driver regulations.
You can overload the vehicle as much as you want, it is yours but there are issues in doing so, one is safety is compromised while another is you now have put yourself into a bad legal position if you get into an accident.
In all reality, as much as I trash some van owners, I would love to see that number pushed up to 16,000 because we now have a number of vehicles that are engineered a lot safer and capable of transporting at higher weights while being the same road vehicles we have used in the past.