Okay, I’m not sure if anyone can help me but here it goes. When I first got the TCA throttle, MSFS thought that one was at 30% and the other at idle when both were in idle. Then I went in and hit reset on the sensitivity and now when I have the throttle at idle, the game sees them as being in the reverse thrust position. Does anyone know how I can calibrate this in the game? As far as I can tell, they are calibrated outside the game but the game itself does not see them as calibrated. Thank you! 
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Not sure if this will help you or not. I set mine up using the rather good app on the flypad in the xperimental version of the FBW A320. Here are my settings as in the throttle.ini file - you could give them a try (back-up your current file first!). Find the file in this location > AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalState\packages\flybywire-aircraft-a320-neo\work - but replace the ‘flybywire…’ folder with whichever 'plane you are using. And here are my settings which you can copy-paste just to try >
[throttle_common]
reverse_on_axis = true
[throttle_axis_1]
reverse_low = -0.980000
reverse_high = -1.000000
reverse_idle_low = -0.810000
reverse_idle_high = -0.750000
idle_low = -0.600000
idle_high = -0.500000
climb_low = -0.220000
climb_high = -0.120000
flex_mct_low = 0.300000
flex_mct_high = 0.397644
toga_low = 0.950000
toga_high = 1.000000
[throttle_axis_2]
reverse_low = -0.980000
reverse_high = -1.000000
reverse_idle_low = -0.810000
reverse_idle_high = -0.750000
idle_low = -0.600000
idle_high = -0.500000
climb_low = -0.220000
climb_high = -0.120000
flex_mct_low = 0.300000
flex_mct_high = 0.395386
toga_low = 0.950000
toga_high = 1.000000