This is correct for getting 40 cm for hipfire and all aims matched to MDH 100% (i.e. the same distance moving to the edge of the monitor). The aim scaling in Hunt is all over the place which is why you get such different numbers for all the aims.
The FOV doesn't change when zooming, it only changes the camera distance to your character. Same when aiming, it just moves the camera even further forward, so it's probably just a 3rd person view thing.