So now we know it: The flat crystal is the reason for the rep being thinner than the gen.
Somehow I have the strange desire to get the Sinn U2 rep right instead of simply buying a gen. Even if it involves similar money. Stupid Chefcook. The rep $240, an ETA 2893-2 $220, The Zigmeister lumework ca $150 (dunno actually) ... hm. Waiting for an updated rep crystal or trying to get a genuine crystal, that is the question a nutter somewhere in the black forrest is losing his sleep over.