I bought a Motorola Bluetooth headset to go with my Motorola Droid. The two chargers have the same plug ends however the outputs listed on the chargers are different: Droid- 5.1 V, 850mA; Headset- 5.0 V, 550mA. It would be handy to use the chargers for either device. Can the chargers be used interchangeably with out problems? Can the lower output headset charger be used with the Droid but not vice-versa? Thanks for the help.