There's a reason for that, and no it is not a lie. Long story short, there's two verisons of Gigabytes. Everybody thinks that 1 GB = 1,000MB. This is true in a generalization sense. However, 1GB is actually 1024MB when it comes down to byte-by-byte of how the computer sees it. When they tell you that you got 200GB, what they are actually telling you, is the Human Term.
Terraria Community Forums
Xylia