It's ridiculous. If you told me 3 months ago that I would gain 1.5 clubs distance but become a worse iron player I'd have said you were nuts.It's funny, my GI iron experience has been a little different. I haven't picked up as much distance as you, around a club, but I feel wildly more accurate with them. My GIR numbers for my last 2 rounds were the highest I've had in the last year and a half. Could have to do with the fact that the CB3's are more of a tweener type iron, though - I don't know if I would call them a full GI stick.
I'm going to keep trying to get better because the distance is intoxicating, but they have been served notice that they better shape up.