ZWave FGK101 activation of second contact

I’m new to the smart home theme with zwave and bought some Devolo LC-13 and now two FGK101.
I tried to use the external contact for a second reed contact to detect if the window is completely open or only sloped.
But I always get the same alarm for both contacts. I tried to configure the FGK101 with Parameter 20 to another type (Flood alarm), but now both concats send “Flood”.
Is it possible to make difference between the internal contact and the external contact?
The examples show the window sensor with a external button. But I think it makes no sense to send an alarm “window open”, when someone rings the bell at the door?

Any help would be appreciated.