Not sure what is going on, but the differences are obviously just down to the market volume, BTS is much much smaller comparatively to MTGx. But it is really interesting how someone doesn't just move in to BTS with fiat and buy through all of the walls, which is so so so easy compared to MTGx, but then again this would mean that these coins have to be for sale on the exchange in the first place I guess. This may then be seen by other un-experinced users and trigger other exchanges into this price range as well. Although I guess I just answered my own question.