The things that should really matter here are:
1. Did the cards arrive without damage?
2. Did the seller perform what was stated in the auction?
There's a major piece that you left out in the first post which came out in a post later on - the seller stated in the auctions that additional wins would combine for an additional $.50. Since the seller didn't knock off the extra $2.50 from your second deal, after you explicitly asked them to do so per the auction conditions, I'd say you have grounds for a negative/neutral and ding to DSR's.