Not necessarily. I think the key word there is shipped. Bioshock was/ is also available for digital download through Steam. The database here gives XBox 360 Bioshock sales worldwide as 1.8 million, leaving PC boxed sales at around 400,000. Steam sales figures aren't published, but it is conceivable that they at least matched or exceeded shipped boxed sales, giving the total quoted of 1 million.
This is conjecture of course, but Doug Lombardi of Valve recently mentioned that total revenues from Steam sales over the last 4 years would surpass all of Valve's combined shipped revenues from 1998 onwards, so it could be possible.







