63.6201% is correct because there's a bug in Apex where it rounds the 4:3 FOV to the nearest whole number before calculating the ADS sensitivity. So in your case, the FOV is 104.330730 hdeg 4:3, but the game rounds this to 104.
The horizontal sensitivity should be the same, but the vertical might have to be lowered to account for the lower FOV.
You can do this by selecting "Custom" under "Y Sensitivity" and set the hipfire Y Axis to MDV:
https://www.mouse-sensitivity.com/?share=57309a398d46d743a40966923303262c
It does what it is supposed to do (MDV 0% based on a FOV of 65 hdeg 4:3), but being a beta there might be some optimization issues.
I can find anything out of the ordinary here though.