TheNoobPolice

Yes, Beenox introduced the Relative mode a few titles ago as a way for Battlefield players to easily convert from it's Uniform Soldier Aiming option with the same default scaling multiplier.

No, the calculation is nothing to do with the screen really, the same scaling applies to the FOV regardless.

The fact you're at 178% should be a first clue - you're already +78% over the top of the monitor. Just as the match point can be outside the edge of one side of your monitor, it can be outside the edge of both.

You have not specified what conversion method you are using, but assuming you are using 0% or some other monitor distance (as there would be no difference on 360 distance) then because the target screen is larger there is a different perspective, and this is what the calculator is compensating for with any monitor distance. The physical distance to the edge of a 24" screen is only 89% of that of a 27" screen.

You don't have to match this, you can totally ignore the factor by setting both screens to the same size in the calculator. You will find your sensitivity feels different in some way regardless of what you do. There is never "true 1:1" matching between different FOV's or screen sizes as an absolute statement, only a "pick what aspect of conversion want to be 1:1". I am not sure what you mean by saying "everyone knows 1:1 sens is 37.89%" as this cannot be true for all definitions of "matched sensitivity".

When I moved to a larger screen temporarily, I made an unscaled resolution that was 24" for 1st person shooters (with black bars) and then just used the 27" for the desktop and 3rd person / controllers games. If you do want to use the full 27" size for everything, then my advice would be to just adapt to the new focal length, you may find your brain just figures this out for you and it feels "the same" very quickly without any changes.

You could do the opposite, and match the new 27" ADS focal length / monitor distance to your 24" hipfire sensitivity, but then the hipfire on 27" is going to be more sensitive vs ADS than it used to be, by a factor of 27/24 = 1.125x

Actually 0% is the only "monitor distance" (because it isn't actually one) that maintains it's relationship regardless of orientation in the world. The velocity at the crosshair is always the same no matter where you look.

You feel slower when you move away from the equator for precisely the same reason it feels slower when you zoom in a lot using 0% - the distortion within screen space. You have to move in a curve on the mouse pad to move in a straight line on your monitor the more you look up or down to the poles, and therefore more distance on the pad is necessary in angles where you naturally have less range of motion (diagonal / more vertically). That's why it's generally a good idea to increase the vertical sensitivity somewhat, at least for ergonomics sake.

It’s because you have changed monitor size, and you are converting to a distance defined on the smaller screen.
if you want to ignore this, just set the same monitor size for both source and target.

Custom Curve software has a feature explicitly for this using the interception driver. It's a one off 10 bucks and available from mouseacceleration.com. You don't have to use any accel features, just use the toggle.

I also wrote a script myself using Autohotkey that leverages interception to do the same thing, the issue with that is AHK is an interpreted language (so "slow" in computational terms ) and would require a polling rate of no greater than 500hz to not cause timing bugs and would still require a few percent of CPU usage every time you hit the toggle.

Not sure what you mean by horizontally correct?

How could they be horizontally incorrect?

All monitor distance functions are effectively a hack to bridge the gap between perceived sensitivity changes and the factual maintaining of crosshair sensitivity (i.e focal length scaling), and viewspeed is just a calculation that arrives at a sensitivity value which could also be expressed as an equivalent monitor distance, only this "equivalent distance" just scales up or down slightly depending on the source and target FOV values.

You haven't shown your target conversion method?
I imagine those numbers are from 0% or similar. When converting from a 3D game using something like 0% then only the velocity of the central pixel on the games FOV will be matched across the whole screen in Osu, this definitely makes it feel very slow.
For this reason, people tend to use a 100% or higher vertical monitor match for that use case.

It's 100% placebo, the coefficient is just a multiplier to the sensitivity, just using trig instead of straight multiplicative values.

It's designed to help people find an overall estimate of turn speed they like the feel of over different FOVS / scopes, which can then be used as barometer for other games relative to hipfire. It is not supposed to be a "golden place on the screen that is matched" as some people have misunderstood it.

This is because if you use the straightforward focal length scaling which is "mathematically correct", then very high zoom scopes start to feel very slow relative to hipfire, and a higher monitor distance can be a better compromise for overall feel without having to set sensitivity multipliers for every zoom level, which most gamers don't want to do. In fact, the majority of players never even touch these options when included in game's advanced menus or config files.

if you set a low sensitivity value with a higher coefficient vs a higher sens value with a lower coefficient -provide they were the exact same degrees per mickey (i.e 360 distance) at the exact same FOV there is no difference whatsoever.