He never diets down for a show, rather he "eats up" for each one. If you ever went back when he was doing 3-4 shows each year (like the O, and then some of those European Grand Prix) you see that every couple of weeks when he did a new show he was always heavier each time.
I asked him once why he didn't train year around and really see what he could do with maxing out his genetic limits and grabbing the Sandow and he told me that if he did that, that would leave him wide open to serious injury an extra 9 months of the year. I think that when he had that muscle tear, that is when it started to affect his head too. After that, he would come back looking awesome, but would never be the real kevin.