I have put a number of things on my scale over the years and found that most industrial Products are not consistent in weight. But Lego pieces are. I use the scale to count bricks all the time. Even relatively large pieces have tiny variations in weight. But Lego packaging on the other hand has a relatively large variation, likeall packaging. I just happened to be breaking down a whole box of Batman series 1, so I weighed 21 foil bags and sorted them out by weight. My scale measured to 0.01 grams.
Well you can see a clear average, but the difference from the lightest package to the heaviest package is 0.11 g. That's huge, when you consider how little the difference is in various figures. I suspect the same will be true of the new cardboard boxes, and when I have enough of them lying around, I will do this again. Unless someone beats me to it.