"The point here is to share information that I simply experienced. It is not a matter of saying whether you are in agreement or not, but in doubt why not experience it yourself and share your own results.
I just find the experience very curious, that’s all** :-)"**
I think the reason you keep getting ‘down-votes’ is because the premise of your post is unclear.
What you’ve shown with your data are that two riders of different weights will have different average power figures when climbing the same distance at essentially the exact same speed. The lighter rider needs to produce significantly fewer watts than the heavier rider. This is not a surprise, just a confirmation that the game physics make sense.
Where (I suspect) you lose people is in the way you’ve presented it.
When I read your post, I took it to mean that you found yourself physically unable to produce the same avg power on the climb after you reduced your Zwift weight. That is, that you rode (somehow) at the *exact same level of exertion* w/ the same trainer resistance and measured only 254 W at 65 kg - even though the same force exerted on the pedals nets you an average of 317 W when your ‘game weight’ is 75 kg.
If this is truly what you meant to say, then it’s hard to wrap one’s head around.
If you, as a 75 kg very fit rider, can put up an avg of 317W on that segment, you ought to be able to do the same w/ a ‘game weight’ of 65 kg - and this would make your avatar climb the Alpe in a much shorter time (assuming you used the same general tactics w/ regard to when and where you’re applying more/less power on both attempts).