I believe it has to do with water levels and grass. The past 5 years have been dominated by the south, but if you look, this year since the water has come back up the north end has been every bit as productive if not better. The 38lb stringer from this past Sunday was caught north and I know that basschamps was won north. The south end has better habitat for big fish with deeper water and deeper grass, but don't count out the north end when the water is up.