Do you have software for the servo drives? Normally with modern AC servos you should be able to hook up to a computer via serial port and monitor everything via software.
You should be able to see what the max +/- errors are and also you should have an inbuilt scope so you can see how the axis is behaving, ie is it over shooting, what the damping is like etc. You should also be able to see what the following error is set to in the software.
Hood