This a small one, but several of the games listed as having precise fov through config or console, actually don't.

Neither Doom 2016, Doom Eternal, and Half life 1 Won Version actually let you set fov in decimal places.  There are more, but those are just the ones that I can point to as an example.  IE you can't set 91.29, only 91.  This is easy to test by simply opening the console during games and seeing there is not a visual change to the fov when trying non whole numbers.  Only 91, 92, etc work. In contrast, something like Quake 3, Crysis, etc does offer precise fov. 

Maybe I'm missing something, but this leads to some problems when trying out fov tricks like focal distance scaling and matching sensitivity to exact angles.  

Some games are missing the FOV range and rounding precision since they were added before this was supported by the calculator. Doom 2016 is one of these games.

Doom Eternal and Half-Life one are registered with no decimal support though. You can still enter multiple decimals, but if you use the Auto FOV function, or switch the FOV Type to the default from another FOV Type, the rounding will be applied.