I had a similar problem already posted in this topic when the afterburn ratio always stays on some default value. For me, it's ~10.5k Rx/Ry value (~83%). I thought SimAppPro has some bug and without a proper explanation of what exactly these settings do, ppl can't understand what result they should have and why they don't get any changes in DCS. The problem was in incorrect afterburner calibration. Don't read what's written in the app. Calibrate it from IDLE to your physical detent, no further!