I know the instructions in my JD mannual are not very clear. If I remember correctly when I am setting the reel speed it depends on how fast I am traveling when I go though the steps in the book. If I am just going 1 mph it will be different than if I am going 5-6 mph when I go through the steps in the book. I have not done it in a while. Mine has worked ok this year so far.
Now I don't cut to fast. I have a 20 ft head on a 9400 and in beans I can only max out about 3.5 mph with out throwing them out the back. But even then at 3.5 mph my setting us usually only on #3 or #4. Any faster and they beat all the beans out of the pod before they get in the head or they all get tangled in the reel.