I was just looking at the cgminer image posted by gateway a few days ago and the work utility value on that screen seems really high for 422GH/s.

I would expect 422GH/s to show WU at about 6K, not the ~11K that is shown.  From the other stats on the screen it appears that it had been hashing for at least 10 minutes, so that should have been enough time for WU to stabilize.