Words can't describe how pleased I am, because I feel he now understands the system. If he uses it day in day out, I am not too worried about what will happen to him when he is a young adult.
I so much feel for you - I don't know what I will do when he is at that stage. I read these terrifying posts on ChildrenWithDiabetes:( I know I only have a limited amount of time before my son is there too.
One approach I am now using is money. I give him cash for every day when he does a good job, a lot of money (I think). I give him $2 for every day when he does strong active management of highs and lows (even if he is somewhat unsuccessful), and $5 for every day he achieves a curve that could pass for normal (I am planning to increase this to $5/$10 when he is in HS).
As a comparison, my college boy was getting $5 "allowance" per week when he was a high school senior - I am a cheapskate. I figure diabetes is like a full time job, and I need to make it worth his while - even if it is a LOT of money for a kid, it is worth it to me that he does it and keeps doing it.
I may be wrong for monetizing his behavior, but if it works I don't care. It's worth a lot more than money to me. There isn't much I wouldn't give to see him actively managing his BG in the upcoming years. I am really afraid of his eventually getting burnout. And I know teenage rebellion for him is just around the corner - it is only a matter of time.