I have a Cherokee airplane with a 70" wing. I have balance the plane every which way. I put it on a level plane and level the airplane. I measure the tip of the wing at both ends and they were the same I measure down both wing in increment of 3" and they were the same Checking for a twisted wing. But in order for this airplane to fly level the ailerons has to be 1/4" up on the right side and 1/4" down on the other side .What could be wrong.