larger DOF on 16-50 on nex6

sorry but i must disagree there, if I was try to make sure the camera focus on exactly what I wanted I would use DMF but in this case I'm trying to eliminate as much "human factor" as possible.  if I manual focused one could simple argue that my focus was off.  But in theory if i shot in center AF, the camera should only focus on the center..unless I totally off base here