Same problem on the SCAR.
If the post is centered in the circle, it is really nice. If it is low, it really messes with my brain. (Which isn't hard)
For some reason I was thinking that real HK sights the hood and post relationship was fixed to prevent this from happening.
But I have only shot a MP5, it wasn't and it was already sighted in. Plus, I had the happy switch on "burn through someone else's ammo" , so I wasn't really doing precision aiming.