Tim, thanks for your reply. I do not believe anything to be wrong, I was just puzzled somewhat.
In my mind, the weight 'at take-off' would be the weight at the moment take-off power is applied - but this is a very minor issue, as said, and we can forget about it.
Being presented a W&B result for 'Landing', I had assumed this is the situation when arriving back at the surface.
The idea behind both interpretations is having W&B within limits all the time while airborne and checking this by means of calculations, which I higly appreciate as a SkyDemon function.
I understand now the presented results consider the situation right after take-off, beginning the climb and joining the circuit for landing, respectively. That is perfectly fine of course.
Finally, I appreciate all of this may not even be of any significance on many flights. It does get interesting on short flights with a small amount of fuel, which is where my question arose from.
Again, thanks for your help, all clear on my side.
Erik