text: ok, so I just checked it out and the elevator definitely only stops at the U4 platform (-3). Then there is also an underground elevator which connects the U4 (-3) and U6 (-2) platforms. And at the opposite end of the U6 platform there is a diagonal elevator to the small B-Ebene (-1) of that end of the U6 platform. So there is definitely no elevator to the B-Ebene (-1) at the Senkcenber-Anlage end of the U6 Platform.
  
  Attached photo(s):
  https://westnordost.de/p/9979.jpg
  https://westnordost.de/p/9980.jpg
  https://westnordost.de/p/9981.jpg
  https://westnordost.de/p/9982.jpg