I'm running Parallels Desktop for MAC, running it "like a MAC." What files are counted towards the Win 7 usage? I suppose that Win programs and their files (like .PST for Outlook) are counted towards the total, but what else is? Are Shared Files and Documents using up both MAC and Win 7 storage?
"Like a Mac" or "Like a PC" have no influence on disk usage, it's just cosmetic, you still have a full installation of Windows and Windows apps in a virtual disk. Shared files and folders exist only once, on the Mac side either you choose "like a Mac" or "like a PC".
The "Shared Profile: Share Mac user folders with Windows" option will change the paths of the selected Windows folders to point to your user folders on the Mac (Desktop, Documents, Pictures, Music, Movies, Downloads, Recycle Bin). Files are either stored on the Mac side or the Windows side. Never both sides.