Isn't it interesting that what starts out from the OP becomes a bash of CA!
I have discovered (in 1967) that Ford pickups have a crimp in the fuel hose between the filler and the tank(s). I have owned a 67, 91 and 11 Ford PU and all three would stop filling 4-6 gallons short. I do not think it has to do with speed of filling. My frustration with Ford PU's was that they did not take into consideration the difference between gas and diesel. The only filler spout is designed for unleaded gasoline.
I now have a Diesel MH with the large filler pipes (both sides of the coach). Let me tell you that when I fuel in the truck lanes, I don't worry about letting the foam settle because there is none. When the pump kicks off, fuel is right at the top of the pipe. This is the high-speed truck pumps. When I first got the unit, I tried to add fuel after the pump kicked off and it ran over. NOTE: THIS IS WHY CA DOES NOT WANT YOU TO CONTINUE FUELING AFTER THE PUMP STOPS. I also notice that when fueling the MH Diesel at regular pumps, when the pump stopped, the filler pipe was full. Hence my reasoning that it is not speed or foam.
Now, with my '11 Ford Ranger Toad, when the pump stops, it will take about 3 more gallons (usually). I did crawl under and lo and behold: The filler hose is crimped over the frame and under the bed! Talk about design flaw! I suspect that other PU Mfgrs do the same thing.
I was challenged one time while filling my truck at Costco, and told the attendant to go watch someone else and if I spilled, I would tell him. So far, I haven't spilled.