Hi there.
The backplate with 'descriptions' of the oxygen system seems to be completely wrong.

As far as I know these backplate belogns to the bomb fuse switch of some other german warbirds.

The markings show
Off (bombs disarmed)
mV (with delay)
oV (without delay)
Waagerecht (level bombing)
Sturz (dive bombing)

And nothing of these markings has to do anything with the oxygen system

Deci