I would not be so hot for the over. The over smells very much like a public play. The Pittsburgh defense is far better than the San Diego defense and may keep KC to 21 or so. They are great against the run, which is KC's biggest threat.
It's a lot easier to score at home when the fans are quiet and rooting for you. Arrowhead is no cakewalk and the PIT offense will not put up 35. They won't get the turnovers off a rookie QB like last week.
If anything I like the under but the over is probably a trap.