Mark,
The lower view is just wrong - the Horizon line is conformal with the actual horizon unless you're up high (say > FL250) where you can see the line slightly above but parallel to the actual visible horizon. At a low level such as shown, it definitely would be conformal.
The only effect you might see with a commercial HUD is that the centerline ("Boresight") of the display is slightly offset to the left by the same amount that actual HUD is physically displaced. This can be a bit distracting when taxying but doesn't appear to be of any consequence when landing especially in CAT III conditions.