Ben Wallace is listed at 6'9" 240lbs, they are approximately the same height. Yet Wallace looks bigger and leaner than James. And James is supposedly 20 lbs heavier.
Those stories get told over and over by different people and the details always get changed every time someone tells it. Next month they'll be saying that he is 290lbs and 0.000% bodyfat, the amazingly low bodyfat level was measured at Gold's Gym venice by Jim Quinn.