question about hastings B@M trade in policy

Ok so i have an idea i was gonna try out friday. Gamestop has a game i can buy at normal price and flip at hastings for double gamestop price. Question is can i can trade multiple copies of the game in one day. Like say i bought 10 copies of the game from gamestop then could i trade all of them in at hastings that same day for store credit.

I cant find anything online in general or the hasting website about there trade in policy.

I thought it was one copy per system. Say one PS4 and one Xbox One that u could trade to Hastings. Hopefully someone else can chime in