What hihat cymbal are you using?
If its the hihat with the speed light, that's a single zone hihat. As for positions, you should be getting way more than 4 levels of open/closed. I got a Roland FD6 and on a edrumin/pearl mimic you can see the gradual open to close. On the 2box, what might look 4 levels is actually more, I am assuming you're looking at the screen, which will approximate the transitions due to the limitation of the screen resolution, but you do get way more than that.