I have been noticing now that I'm back in school a zone about 2/3 to the left and 2/3 up from bottom of the screen where the pen is read higher or lower than it actually is depend on where in this spot you are. It's about the size of a circus peanut and it's driving me ballistic. Is the a way to recalibrate the spen or am I going to have to get this repaired. Rooted.