I don't think that's the case. If anything, SM and avex closely work together (most of SM's Japanese releases are under avex), so that would seem to facilitate the exchange. As for "Mirotic" (and other similar cases) - it was exclusive to Asia, while "Under My Skin" was intended for Europe. Remember, that was back in the day when K-Pop wasn't nearly as popular as it is now. Nothig greedy here to me - the writers simply secured themselves more exposure for the song instead of wasting it. The more people hear such a bop, the better.