Adjusting your wing angles may solve your problem but I would think that there is another reason. I use a laser level to line the wing up with the horizontal stabilizer, one side at a time. I had a similar problem and the problem started with too little right thrust! When I got the right thrust adjusted I needed less right rudder to get the plane to fly straight and suddenly it was tracking better in the loops. It seems that with some designs you need less rudder in a loop than when flying straight. To solve the problem fast before my last competition I made a mix that reduced left rudder when I pull up elevator, this worked well but is not the best solution.