Im not quite sure I understand all of your first post, since we are able to bill all insurance companies and stuff, and i don't understand the drug testing part either.
But it seems that you know the DNP is pretty much worthless, which means your ahead of most people on this forum. There is no logical reason to go back and get your DNP, its just to make colleges money. I guess if your hard set on being called doctor you can but that isn't a reason to get a degree, just to be called doctor.
Soon will be the time with doctorate prepared nurses wiping tail at the bedside 80000 in debt.