I didn't want to sound like smartass but bringing Coleman into discussion is plain silly. The guy is obviously on steroids like every pro bodybuilder and it's silly to compare him to any regular guy. Also Coleman is not always at 4% of body fat, it would be almost impossible to stay at that level for whole year IMO. Those % are probably before competitions he takes.
I have a friend who turned pro, he was huge but fatty, now he is lean as hell, he's on roids too. Roids are great for pro's, they help you burn fat and build muscle, however I don't support guys taking them just to get bigger with no real goals. In other words, only pro's should take them at some level.
Also to make myself clear, I've never said I'm pro bulking or anti bulking guy, what I tried to say is that Dule's logic have some faults, or simply I don't agree with him on many things. My point is that gaining some fat while you're gaining muscles is not that bad, like Dule presents, and I'm 100% sure that you can gain more than 2kg's of lean muscle per year.