When converting from desktop to CS:GO (400 dpi 1080p), I get the result of 2.51563 (41.3054 cm ).

Desktop to Battlefield 4 Hipfire (400 dpi 1080p) gives 0.014445 (51.2964 cm )

Shouldn't the cm/360 rotation be the same?

By converting the 2.51563 I got from CS:GO to Battlefield 4, I got the result of 0.019148 which does not match the 0.014445 that the desktop mode gave me.

This might seem a little counterintuitive at first, but the reason is that the Desktop conversion matches your FOV to the desktop. So if you have different FOV, you will get different sensitivity. If you set the BF4 fov to the same as CS:GO, you will get the same 360 distance

 

Desktop works by making the distance your crosshair have to move to a certain object on screen in the game, to the same distance your cursor have to move to the same point on the screen in Windows.