Ubuntu actively syncs packages with Debian. There are some diffs even in the core packages, but they are not that big. But then again, what was he checking: Ubuntu Main or Main+Universe? (I suppose that the sizes of Restricted and Multiverse are, in LOC, rather small, so they don't really matter). Main+Universe is roughly comparable to Debian's Main. I suspect (though didn't really check) that there is a higher ratio of GNU programs in the core (Ubuntu's Main) than in the peripherials.
If I'm right, you'll find a higher ration of GNU code in RHEL/Centos than in Fedora (of a "comparable generation"), and likewise in SLES compared to openSUSE (Did I get the names right?).