The numbers are probably pretty close. Lets not forget that its only an estimate and probably at worse only off by less then 10% give or take.
Stores like Best Buy and Wal Mart make razer thin margins on all consoles. In fact its less then 5% which by the time the store pays for the distribution through their own channels and then the employee's that stock and sell it they only break even on the system hardware. The store has the same incentive, sell lots of consoles and you will likely sell more games. The stores make approximately 20 % on all software, controllers, and accessories that are sold at MSRP (thats $12 per $60 game).