So I decided to move all the control rods one notch closer to all the control surfaces on my Apprentice S in order to give me more manovorabilty. After this, I trimmed the surfaces as best I could on the ground and then sent the plane up. It was all working fine and I was able to move around a lot more and then I decided to go around at a higher speed. It became apparent that at high speeds, the tail would buffet violently and jerk the plane around. I was guessing that it was an elevator issue so I played around with the trim but no difference so I brought it down, changed the rods to where they were originally and it flew perfect. Does anyone know why this happened or how I can get around it?