Xbox 360 NPD and our attach ratios are vastly different: Explanations?

[FreeTalkLive]

TWRoO said:
First... @Oyv. The attach ratio MS states is from NPD

It is true NPD does not count bundled games.... but unless there are some I don't know about, they don't account for that much.

The Christmas bundles (Sega Superstar Tennis, Lego Indiana Jones, Kung Fu Panda and in 2007 Forza 2 and Marvel:Ultimate Alliance) account for only about 8 million sales..... which should be about 0.5 on the attach ratio.

In other words if NPD had tracked them, it would be 8.6ish instead of 8.1

I thought other games had previously been bundled with Xbox 360, like Halo 3.