I agree. The PHITZ-part made me suspicious, too. PHITZ- I haven't seen in German names, but as you say, there is PFITZ- like in PFITZ(N)ER. This is from PFÜTZNER (with a U umlaut), originally somebody living by a "Pfütze" (puddle, pool). Bow the combination with Mayer may be coincidential, but it does make sense: "farmer by the pool".