Okay, that does make sense, actually. Setting sensitivity over 50 or 100 or so, depending on your mouse's DPI, will simply cause you to hit the game's own turn speed limit pretty much immediately. All swipes that are over the limit are effectively *at* the limit, so if you hit the limit at 100, it should look the same all the way up to 500.
So, your sensitivity is updating, which is good. However, that does leave the question of how you were able to turn, still, when you set sensitivity to 0. To the best of my knowledge, it is not possible to set Sensitivity to 0 and still be able to turn. Are you able to reproduce this?
If you are sable to reproduce it, a video of it happening would be helpful. Show us the XIM4 Manager screen and scroll through the current settings (make sure to open Advanced sections so we can see everything), the XIM4 itself, and the TV/monitor, preferably all while moving the mouse. If that really is happening somehow, then something would almost certainly have to be wrong with your XIM4.