I've been having lots of trouble with my two-handed backhand, left hand on bottom, using my APDC... it used to be my best sided shot. I hit it flat, and always have. Lately, though, the ball, when hit flat, either hits the bottom of the net or takes-off and hits the back fence!!! This is unacceptable, and I am having a huge problem fixing it! I don't think it's my racquet, b/c my shot from the two-handed forehand (left hand on bottom, flat as well) has improved with this racquet. The string, if it matters, is nat gut 16, strung at approx. 60lbs. Any advice on how I can rein in this shot?