Halo 3 perorders 4 million?

[Smashchu]

When I first read it, I was like "OMG!", but after i thought about it, it made sences.

 

The people who bought a 360 are likely to buy Halo 3. These people are also likely to pre-order a game. I assum it will push systems, but this 4 million is likely from people who own a 360(atleast 75%).