You will need to set higher gain compared to the blue stick because the airspy has no amplifier built in.
(Probably 21)
Also you should refer to optimum command line option in this post:
(Problem with port 30104 & Airspy Mini/Odroid XU4 - #33 by prog)
I believe the FlightFeeder just has a different Position counting towards flightaware. Wouldn’t worry too much about it.
Hmm seems your FlightFeeder has some better range for you but that could just be a higher gain being set (if i remember your display correctly you had way more >-3dBFS message on the feeder compared ot your othe rig)