I recently booked a KLM flight on NW.com for an intra-europe trip in which appeared to be class L and N on the flights. My SkyTeam carrier does not credit N fares on KLM, so I was a bit dissapointed, but it was cheap enough. However, when I received my boarding pass, I noticed I was in class M on both flights. I'm not complaining now, but how does this happen?