If they knew the problem, why would they run it for a long time? My motor did all the leg work for yours. They put over 6 hours of run time on my 180rx in flight making sure all the adjustments were correct for "the fix." They probably opened your motor, noted the problem, fixed the problem, test ran it and it was good. I now have what amounts to a brand new engine. Accel is astounding and static thrust is incredible. Try it you will see. Also how many hours are on your engine? It wouldn't make sense to service an engine that has a 50hr service interval with very little time on it. Services are not free and they probably wanted to save you money.