The Germans have always put thier optics up higher, just go to the JANES small arms weapons, Small Arms of the World, Etc. Books.
Actually they work very well at those ht's, and Germany isn't the only country that put the optic's higher than the Irons. We also have, and on many weapons to include the M16 carry handle, with the iron sight see thru under the optic's. Magnified optics are not to be compaired with the red dot/reflex shooting, as the (no) mag optic's (except the excelent Swarovski Cobra ring/dot 1.5 Mag) are in place of the iron's. The Mag optic's are for a dif. purpose and shouldn't be as low as the Mag's, as you can't look thru the Mag optic and use your irons if the Mag optic crashes for some reason. The Irons are usually viewed under the mag. optic's for that reason. The Acog has the back up iron on top for reel fast (close in no time to realy aim purposes).
Good shootin, Jack