taskmgr and procexp report the same high numbers for me.
i'm under the impression that the numbers you see for a given process include all of an app's references to dlls; this would be the minimum it would use if it were the only process running (which is similar to what ps in *n?x does, i believe).

lazy searching got me no explanation of how this number is calculated. i did observe years ago that winxp's taskmgr reports higher numbers than win2k, but it must be that this calculation is very complex if no one ever tries to explain in detail how it's derived.

that said, jugg's explanation sounds good to me :)