Both my Class A's (90 gallon tanks) had the same problem OP is having and both have Frieghtliner chassis. What I learned from the 1st rig was to just put the nose of the nozzle half way into the filler tube. And to just go to the first fill click on the handle. Sure it's slower than if I try to set the handle at fast fill on the 3rd click, but it's much less annoying as it doesn't snap off every 3-4 gallons. Naturally, I have to stand there and hold the nozzle for safety reasons if I only put the tip of the nozzle in the filler tube, but I generally do my window washing when I arrive at or leave a campground. If I must do it at the station, (most of which just put a drop of soap in the window washing tanks), there are times when I have to finish filling first, but still, it's way under 30 minutes.
Occasionally, I can put the nozzle nose into the filler tube half way and set it on the first click. Those times I can do the windshields without holding onto the handle. So it seems there's a difference in how the stations nozzles behave, and of course ambient temp and pressure play a role.
But as far as taking 30 minutes to fill? Even in the worse of circumstances, pulling the nose of the nozzle out half way while filling does the trick for me and I rarely need more than 15 minutes. Most of that is waiting for a spot to open.
AFA using the truck nozzles? Since they don't fit in the RV filler tube I have to stand there holding the nozzle in place. Not fun when you're putting in 55 gallons or so. Especially in bad or cold weather. So I stick to the car pumps.