Yes, I fully agree that this doesn’t make any sense.
I just tried to follow the previous topic about similar question (TTree Weighting is different from TH1 weighting), where one of the final responses was:
" I believe the standard way is to add a weight branch with the weight. You can do the multiplication later: the information will be fully available in the tree."
So now I am trying how it should be done.
Thanks for your help.