when connected to a Y-harness, they are supposed to move in the same direction. You need to change the pushrod setup. They need to be on opposite sides of the servos. For example, install one control rod so it is on the outside of a servo (by outside, I mean on the arm pointing to the wingtip), and then on the other wing panel, put that rod on the outside (again, on the arm pointing toward the wingtip). I am guessing that you have one on the "outside" and one of the "inside" which would make them move the same direction.