Again consumption CDI, too high?!?!

Hello! I have a C220CDI T Mopf Autom. with RPF since 2600km and am in despair with the consumption!! I drive really moderate and need on average 8.6L! Landstrasse about 7.6-8,0L, in the city likes times over 9. I used with the same behavior/routes with the Passat TDI 115PS 5,5-7L, that can not be or?? I do it already so often the air conditioning goes off and hold back very much. The workshop says there I have to drive 10000km so that the less, the But I think it’s a fairy tale. How are your experiences with this topic, can someone help me? Diesel Greetings Ramair