It's all bull, gn-zer... A dealer will not walk away from a deal if he's making money... Especially these days... Keep in mind that even after he sells you the truck the factory pays him a "hold back" which amounts to anywhere from $600 to $2000, depending on the unit...
You can believe me on this one... I come from a auto industry family and owned my own dealership for close to 15 years...