One important consideration relates to what the empty W&B actual data is.
Without boring you with this and that, suffice it to say that, if the starting weight and CG is not reasonably accurate, all bets are off regardless of how you might go about calculating the loaded weight and CG. If things don't appear to be right, and you can't figure out a sensible reason when checking the sums .... the first port of call is a reweigh to rezero the base data ....