i have the magnet aligned and it does work above 11km/h. The problem is below 11km/h, when I get erratic readings.
I used the following instructions to access all options but the power: https://drive.google.com/open?id=1ZiNNZGAxnzcrLzeHtNl-dOtNR-QwFUNB
You stated that the power is hardcoded, but...