Canon 60D: Has Canon Secretly Improved the 60D Auto Focus and Kept It Hush Hush?

Continuing on in my testing of my new Canon 60D, I'm impressed with the auto focus. It seems much snappier and has less out of focus images than say my Canon T2i 550D or my previous Canon 40D for example.

Has Canon snuck in some improvements to the Canon 60D Auto Focus? Yes, the 60D has more cross-type sensors, but I'm a focus / recompose shooter for the most part so I wouldn't think these would make a difference.

Shooting both, I certainly get the impression that my Canon 60D is faster and more accurate than my Canon 550D (T2i).

Here's a couple of possible explanations...