If you have a look at the dedicated thread I mentioned above :
It is only related to the heigth ratio (a percentage of the altitude expressed in % not in altitude ‘meters’) between take-off (the 0% point in green) and the maximum altitude reached during the flight (the 100% height in red) and it is not related to the geo limit).
At 80%, it will be orange, at 50% it should be yellow...
You take-off vertically up to 10 m and you fly down with a regular descent slope 30 meter in front of you, you will see a red line at the beginning (the green from the ‘0’ point is not visible because over-riden by the 10m maximum heigth of the flight just above take off point), then for the next 30 meters of the descending flight, you will see a succession of orange, yellow, yellow-greenish, light green, dark green colors. The dark green corresponds to the landing point.