They are sighted for and testfired at 25 meters, as opposed to the P08 which was sighted for and testfired at 50 meters.
With a 29/70-ish version in .30 luger with 6 inch barrel, point of aim (top of the sights line up) should be point of impact. Flinching can produce low shots as well, a luger will usually shoot higher than point of aim, not lower.
With the P08 it helps to ignore the rear sight and just point the front sight into the general direction
The combination of a P08 and subsonic 145gr bullets considerably lowers the point of impact.