The only time I have seen this done is to check a mod to ensure the PCB board is up to snuff and delivering the correct voltage for the
batteries used. And this is typically done with the mod open using aligator clips at the internal connection of the atty connector so when the atty is activated you can see the drop in voltage when a load is applied. The aligator clips (miniture jumper cables) for lack of a better description provide hands free operation cliping them to the connector and then to the multimeter leads, this way you dont need three hands to hold everything push the button and watch the meter.
Dan