Originally Posted by mixture
Erm ... surely they cost just the same, just turn them round 180 degrees and there you have it ..... a rear facing seat.
Not being a techie, but If I remember correctly, forward facing seats just have a break point (set pretty low) so that with a little pressure from behind, you can fold them forward to aid evacuation / decelerate your forhead on it. Hence the rigidity of the backrest is pretty low.
If you turned the seats, I would expect them to be sturdier as you would not want them folding over backwards and breaking your back.
That could explain why you can't / shoudln't just turn the same seats around.