I copied this over from another thread because it belongs here.
If you are using incandescent bulbs and you desire to go lower that is a con. However I believe the reason the factory firmware limits it to 20% is because this device is a repair part for the Gardinier fan which uses LED’s and it would make sense that below 20% the LED’s might start working inconsistently or when going from off to on 20% was the amount needed to get them to illuminate.