Yes, that's right. That's because the savings potentials of the different functions can't simply be added up, because they can influence each other.
For example: thanks to the Geofencing, your tado° app knows when residents are in the house or apartment and when they are not. So the heating is turned down when no one is home. However, if the sun shines into the empty apartment for a few hours, the heating is not turned down as much again, so that energy is not saved to the full extent with both functions at the same time.