My standard check on this sort of tool is to see how it handles the Sam & Max games. Because they're only sold as a bundle [1], but they show up in your game list as a bunch of episodes. The general failure mode of the tools is to think that each episode costs the full bundle price.

This tool, indeed, does that. [2]

(It doing that lets me feel slightly better about my $7k account valuation.)

[1] http://store.steampowered.com/app/901660/

[2] https://dl.dropbox.com/u/1372532/Screenshots/Screen%20Shot%2...