Its is common practice in the industry for retailers to return products that do not sell well or at all (this is for all types of products and not just limited to video games)
In most cases though, for the publisher to keep sales numbers on their books, they discount the original wholesale price of the game. When the 30-day payment period is up, instead of a 2% discount, the retailer might receive a 10% discount for the game when the amount becomes due. (Generally speaking, in business, you receive the product first than pay within a 30-day window. The seller records the sale upon shippment or delivery).
The publisher would then record this additional discount as a loss via the next quarters books.
Sony can say they shipped 1 Million, but most likely what occured was a larger than normal discount on the wholesale prices enticing retailers to keep copies of the game rather than return them as part of the agreement to get a bigger discount.
Considering the holiday shopping season coming up ... it would be foolish to discount something that would not drive foot traffic. I do not see more people coming to a best buy because motorstorm was $10 cheaper. It makes more sense to sell the game at full price to people who want it and pocket a bigger profit.
Then again, both NPD, GFK & VgChartz could have severly undertracked MotorStorm. In the end they are all estimates and Sony would know best on how many units was actually shipped.
