Particularly, changing the size and position of the deadzone doesn't seem to change how the mouse controls at all. If it's close enough, it will always snap to the center as if the deadzone was still there. Additionally, the "When Off Screen" options don't seem to have an effect either, it always snaps back to the middle when approaching the edge of the screen.
This happens specifically for the "As Mouse" option, calibration seems to work fine for any other purpose. I would assume this is less of a bug and more so just missing functionality.