Enforcement on the punt return that never was

[InsideTheStripe]

NFL Videos: The punt return that never was

Can anyone explain the enforcement of the hold called on Corey Graham during the punt return in the video?

Assuming one is willing to concede that he grabbed Bush inside the shirt/pads and gave him a tug that took him off stride and effected his ability to cover the punt (which I am), I'm scratching my head at the enforcement spot and the placement of the ball to start the series. The hold took place at around the 37 and the ball was caught at the 11. The flag landed at the 18 or so and the enforcement seemed to be half the distance from there?!?

I don't have the 2011 NFL rule book, but something doesn't seem to add up.