that might also explain why recalibrating on the sidewinder works. Because after calibration the sidewinder will then give 100% at the 100% level set on the spektrum, instead of only 80% from the factory settings.

So in short, its a spektrum issue, not a speed controller issue, but some speed controllers do have a fix for it. taking the servo adjust to 125% is a good workaround.

Would you need to have spektrum mixing active to do that?