Ive seen some people trading big amounts of FC and LTC payin around 12 - 15 LCT per 1000 FC.

Im asking myself why do people do that? I mean if you compare the difficulty, 374.94602749 (Litecoin) to 14.27208129 (FC) and keep in mind that the FC-blocks are 200 and not 50 coins worth, 1000 FC should be worth around 9.5 LC right now (14.27208129 / 374.94602749 / 4) = 9.51 LTC per 1000 FC

Or is my calculation wrong? Right now, there seems to be no reason to keep any miners on LTC.