a CG towards the aft of the limit is helping you to safe fuel, the stabilizer always is creating some nose down force with the lift it produces, if you think the stabilizer of a 777 has about the area of a 737 wing, so you could imagine what i am talking about, if you go for an aft center of gravity you might counter this force, a CG of 32 is not uncommon to me and on a long range flight (5000 miles or more) it could safe you a ton of fuel at least. some companies even implied an aft center of gravity policy!