PS VITA / PsTV Calibrate analog sticks?

[SelenitaDelSur]

Hi. I was checking my Vita with the VitaTester homebrew and I noticed that the right stick has a value of 144 when idle on the Y axis, while X (and both axes of left stick) has a value of 126 or so. Is it normal? It is not moving by itself and I have not seen any weird behaviour when playing. But shouldn't the value be closer to the half of the max value, 255? I've been doing the calibration thing rotating the stick counter-clockwise and then clockwise, but the result is the same.

Thanks in advance.