According to scketch:
xval = analogRead(accelpinx); // read the accel value 0 - 1023
yval = analogRead(accelpiny);
xpotcor = analogRead(xpotpin);
ypotcor = analogRead(ypotpin);
pots are used to correct position. It's common practice in automatic regulated system to have a manual control . for correction or emergency. Think about autopilot, you always could turn it off.