Jimmy Crack Corn, you are mostly right. Illinois is hurting very badly for money and they canned a bunch of state troopers. From my understanding is the ones they kept where based on how many tickets the trooper wrote. The courts there have backed up the troopers. In actually reading the law I could see how a police officer and judge could twist it. Another law they twisted was the ag exemption for a CDL. Most states, Illinois included has an exemption if you are hauling grain or livestock in a 100-150 mile radius of the farm and not engage in "Interstate" commerce. They have nabbed a bunch of drivers delivering grain to the local elevator stating that they are engaging in "Interstate Commerce" as the elevator is selling the grain out of state. Again this is Illinois, not indiana. The problem is that the vehicle codes are written just vague enough that the police and courts have to much leeway. Most Traffic tickets can not be tried as a jury trial, you are at the mercy of the judge.
In driving across country for another example. Many of the western states require all trucks pulling trailers to weigh in, even pickup trucks with goosenecks. They were not looking for CDL per say but trying to nab the people driving grossly overweight with a pickup/gooseneck and having brake failures going down the mountains killing people. That is the biggest problem I have with pickups and goosenecks, the new diesels will pull it, but they have problems stopping it due to lack of brake size.
Did your 6.4 have the particulate filter but not the urea? Not as familar with the fords but with the dodges, when they put the particulate filter on they lost 4 mpg or so. If you would remove the filter and reprogram you got it back. Almost everyone regained the fuel economy when they started putting the SCR on the engines. Tractors and big trucks were the same way.