It is officially a second sale, they're just giving you a similar percentage of trade in credit that used to exist in the original Xbox / PS days (EB games would give you $40 for a traded in game that cost $50 brand new, and turn around and sell it for $45 used). Too bad they got so greedy. Regardless, they can still turn around and sell used copies of the present gen version, and make megabucks off of it with their normal used sales profits, so they're really not losing much of anything.
Honestly, anyone not getting a new system should wait until a week after the launch of the new systems to get any of these trade in games, as they're likely to have used copies galore.