I always got the feeling "matches" was more based on paid advertisement then actual matches. i.e. advertisers for X, Y, Z, you bought A and X is closest so they send you X instead of Y and Z even though X is different then A. I never bough from CA, but when they had some good sales on BDs I registered and got some, after that they sent me "matches" that had nothing to do with what I bought and even sometimes for HD DVDs. I bought HD movies, so they must be the same.