Your experiments with the recipe sound delicious!
I wish I could answer your dough structure question with confidence. I’m enough of a scientist to observe, note, and modify; but not enough of a scientist to understand the why of my results much of the time. My off-the-cuff theory would be that the sugar in the apple sauce (as well as a bit coming off the dried fruit) does some good toward feeding the starter in the dough. So maybe the excess dough weight is buoyed somewhat by a good strong fermentation. Or we could chalk this up to the miracles and mysteries of bread baking.
You’ve inspired me to bake this bread again in the coming week, maybe trying some new nuts and fruit and also the cocao nibs @charlesvk and @peevee inspired me to buy a while back. Thanks for sharing your experience with the recipe!