Wierd Discrepancy in Programs and Features

[Outlawstar15a2]

I have Medieval 2 Total War installed along with the Broken Crescent 2.02, Third Age Total War 1.2, and Stainless Steel 6.2 mods. Medieval 2 and all the mods are working fine, my OS is peachy except for one thing. In programs and features Medieval 2 is reported as using 29.0 GB of space Third Age Total War v1.0 patch, 1.1, and 1.2 each are using 29.0 GB when I went to Medieval 2's folder it's reporting a disk size of 32.7 GB and that would included the three submods, Third Age is reporting as using 3.43 GB of disk space when viewing the folder. The sizes reported in Windows Explorer matches the sizes of the mod and game when I downloaded the mod and I "acquired" Medieval 2. I know the size as reported in Programs and Features is wrong but can somebody tell me why Vista is reporting it as such?