Have you noted it specifically is off center in calibration? Or does it just feel off a bit?
I mean, you calibrate it, leave it, then go back into the windows game controller, and it's no loner center, right?
USB, right? Have you tried other sockets? A powered USB hub, if you have one? Those have been known to solve a number of USB issues joystick issues, since your PC setup and its power consumption may or may not have adequate power flowing through the USB plugs to do what the AV8R needs. Try different plugs in the back or front of your computer. If your monitor has USB plugs in it (many do) try that as well.
If you have a ton of other USB things plugged in as well that you don't need or use much you can try unplugging some. I know there are a lot of "gadgets" like cup warmers, webcams, etc, that are all pulling some power through the USB plug that could be making things worse.