when you install the spring seats\perches your axle most likely was not perfectly vertical during the install, the slightest tilt forward or backward of the axle will change the geometry of the wheel alignment whether it kicks the wheel inward on one side vs kicking the wheel outward on other side. Turning the axle left to right or 180 degrees will not cure the problem you have. Most trailer axles are cambered\arched for a reason, it compensates the load so the tires are planted evenly on the road & wears evenly when the load is applied. Dexter Flip Kit or over under kit will solve the problem. It does away with miscalculating the seat's in the wrong position.