Yes i think you're really onto something and it's part of a much broader discussion. There's a lot of negativity around the two year subsidized plans by telcos in the US. Yet would people be upgrading their iPhone's without these programs? Is the iPhone unique vs laptops and tablets? Or would iPhone sales drop dramatically if those programs disappeared as if we had to pay the full price out of pocket the refresh cycle would move out 12 - 24 months.