I have 40GB in there, but only 830GB data. I suspect that it is deleted test data from Europe-north-1.
Sorry, but I have to disagree there. TiB & co. have surfaced only recently and way back when I learned about computing we only had kB for floppy disks and RAM, and MB for hard disks. They were always power of 2, except for HDDs, so the manufacturers could make them look bigger. With MB the difference was small, so it didn’t matter much, but with TB sized drives it does matter.
RAM is to this day sold in GB and they are definitely the power of 2 variety. I don’t know about SSDs, since they use a technology similar to RAM.