Hi, I just got a New Ds lite to replace my old one and I noticed something odd. When I rand Colors I noticed that the pressure sensitivity worked BUT I had to push a lot harder on the far left and right sides towards the middle. The closer i got to the middle of both sides, the harder I had to press. AND i couldn't even get the same darkness I could in the center of the screen. please, is screen defective? or are all new screens this way?