Hi
I think it is a problem that cruise profiles are based on IAS instead of TAS. No propeller airplane can maintain the same IAS when altitude increases, and most POHs show TAS in their performance tables, not IAS.

Consider a standard profile which gives 100 kt at sea level. At most aircraft, the aircraft is still able to maintain 100 kt TAS at FL100, but when skydemon calculates TAS, 100 kt IAS will give about 116 kt TAS, which is not realistic for prop aircraft.

Consider changing this to TAS or let users choose between IAS or TAS when creating profiles.

Regards
Karsten