How much power should a ductless A/C system use while "off"?
Your unit is probably a Heat Pump.  I sell these and I'm not aware of any companies that still sell a/c only units since the cost difference was minimal they have been phased out.  So being a heat pump it would have a crankcase heater either under or wrapped around the compressor.  As long as the main power switch is on the heater will be energized whenever the compressor is off.  That is to keep the oil in the system liquid so it can mix with the refrigerant gas when in operation.  It is a resistance type heater so the wattage seems reasonable.