camber control like 2 part elevator and stab has more control power at extreme throws than a full flying stabilator has. Jets use full flying because of supersonic compressability issues, in other words moving the LE becomes more effective then the TE.
I am no expert but this is what i've read on DJ aerotech, and i agree with what Dick is saying about too much Balance surface is not good either. I like mass balancing my tabs to lessen flutter tendency