Joe I am not being a wise guy at all here but can you explain what kind of common line voltage troubleshooting requires such precise measurements?
Give me a solenoid tester with continuity function and I can troubleshoot most any
typical lighting or power problem.
Many times (and I am guilty of it as well) I think folks just want to look 'cool' with more meter than is necessary. [Add Tim the tool man grunt here]
Of course there are times when you need to bring out the big guns.
But troubleshooting a lighting outlet with a DMM is IMO like using a sledge hammer to drive a finish nail.
JMO, Bob