I have never string a racquet before so I used my old Wilson Energy racquet (bought from K-mart for $15 so you know what it is) for the first-time trial. I am using the Gamma X-2 stringer. The racquet says 50-60 lbs recommended tension. I choose to use 60 Lb and after the mains, I found my racquet deformed into a round shape. :-? The photo is below. So is it because the crap racquet itself or I used too much lbs?