Incorrect files sizes?

Ok, this is kind of odd.
Flight Simulator and other chat
https://forums.simviation.com/phpBB3/
https://forums.simviation.com/phpBB3/viewtopic.php?f=9&t=22935
That's due to the File Allocation Table that is written when formatted.
Also it doesn't show the OS partition. My main disk is 40gb but only registers as 31gb due to the OS partition and NTFS table taking up that space.