Yes, I had it off.
Is there a minimum sensitivity then? If I plug in my sensitivities (22.5in 360 @ 74 vert fov) then using the same DPI, it recommends a sensitivity of:
MouseSensitivity=0.603568
MouseADSSensitivityModifier=0.817742
However, when I use these the sensitivity is significantly higher (maybe 80%) at the same field of view. Nothing I set in the config file seems to actually change the mouse sensitivity except the whole integer values >= 1.
EDIT: Halving my DPI and using the new recommended sensitivity seems accurate. It appears 1 is acting as a minimum.