I had to look at the code, since I don't use it.
MaxAxisLockRate is what decides whether you're in axislock or not, based on stick input. So you need to stick under these 10°/s.
MaxAxisLock is the maximum deviation it will integrate and try to get rid of, when in axislock mode. It will accumulate up to 45° of error.
If your stick input throws you out of axislock, the integrator above gets zeroed.