That's what I picked up from it too - he's not ready to go yet, but he'd like the choice to go at a time of his choosing as opposed to being forced out in a way that Chris Moyles was, for example.
I would like to see Scott stay at Radio 1 until at least the end of this decade, anyway. I have no idea when he actually celebrates his 20 year anniversary at the station though. I know it's definitely this year. Would it be around the same time as Aled, perhaps?