I would agree that the BMWUSA web site is out-of-date and does have errors.
For example, the build your own X5 diesel shows a $900 tax credit fot 2010 models currently being sold, shipped, and delivered.
Yet, look at this spot on the BMWUSA site:
BMW North America
It says you get an $1,800 tax credit with the X5 diesel, and references no model year.
So either the $900 in the build your own is a mistake in the update, or the part of the website in the link above is out-of-date.
The BMWUSA website obviously has an error either way.
I wonder how long it will take before they fix it, one way or the other?