I do agree with the differences in F between MUC and FRA for the FAs. FRA quality varies a lot, MUC always good.
However my experience is the opposite for the pursers: FRA a lot more engaged to take care and making sure everything works fine; MUC: in some flights you see them only once - a long time into the flight, standing in front of you with the manifest in the hand ("let me find your name"), saying: "hello, I think you know how it works" and then never seen again ...
At least to Asia it was generally the case - didn't had for a long time F to the US from MUC...