I'm running the adventure for 3 PCs, and the adjustments for some encounters seem like they're scaled for 4th edition (-40 hp per enemy for 1 fewer PC was seen, for one). I also notice that enemies have a very high number of hit points. Black Horse Thugs have hit points like they're 7th level but attack like they're 1st level. There's an NPC in the first adventure who has more hit dice than most Ancient Dragons. Is this a result of bringing over hit point totals from a previous edition, or are all fights intended to be difficult and long?