I purchased a brand new proturn 260 last year. Good machine, except I notice it leaves 2 mohawks when i'm not going straight. Even sometimes in particular areas when I am going straight. They're usually less than an inch in width and located right in the middle of the blades on the outside. Middle seems fine. figured it was maybe my blades getting worn out, so i switched in a new pair, but the samething is occurring. Tension seems fine. Any ideas?