I’m sure the defenders of Hunter are playing semantics in this situation. They are truly desperate and when push comes to shove I’ll bet all of it is real.
If anything, my guess is that the 450 GB represents the total amount of Data retrieved.
One way to find “more” data than previously reported is if you find a compressed file and manage to decompress it. Previously it might have been categorized as either unimportant, unreadable, or “deleted” data.
450/500GB of data is a LOT. So far we’ve seen a few pictures of Hunter with his meth pipe. A lot more could drop.
There could also be compression that can cut almost half of text, not much on images or audio or executables.