I've been scanning books, and using -Deskew, and this feature is truly awesome. It works every single time and perfectly aligns the pages. Every once in awhile I check to see if a line of text is aligned to be completely level, and it always is. This feature is truly amazing, and I'm surprised I haven't seen more people raving about it before.
I don't know what the parameter is supposed to be for, but it always seems to work the same way with 20% or 40%, so whatever. It's awesome and it works. Keep up the great work, Wizards!
![Smile :)](./images/smilies/icon_smile.gif)