How does Unreal calculates mouse deltas? (<get mouse y/x> <get input mouse delta>

Hi! I am curious about the way Unreal calculates delta for the mouse movements because If get how much the mouse moved in one frame like this:

I get pretty high values:

image

and if I use engines deltas like this:

image

values are a lot lower:

image

reading the mouse x or mouse Y events give same values as get deltas:

image

image

much lower than manually subtract current position with last position…I also tried to multiply by delta seconds because maybe it was something like a speed factor but no.

Does anyone knows what is the real math in unreal to get mouse deltas?