Dear Dave,
It's a happy occurrence to see the author of this invaluable software posting on Translatum!
MS Excel does not seem to handle this function well on its own, even in the 2007 version, so the Duplicate Master is a life saver for those of us working on large compilation type files.
The addition of the options you mention would surely be met with great enthusiasm, so I hope that you do get around to creating a new version. :-)