This is an actual question. I'm in a rather progressed guild, 11/13 HM for 25-man. For familiarization purpose, we started forming 10-mans to practice the mechanics of fights like council and Al'Akir. Al'Akir went down in under one raid night, and another thread lists it as one of the higher-end fights for difficulty in 10-man. I just find this a bit surprising as even some of the easier kills we've gotten such as Mal or Halfus took between two or three raid nights.