This is what I mean, measuring variance by day. I counter your question with, what does variance by hand matter?
variance by hand says how much of a bankroll you need. It says how much of a swing you should expect.

IF loseing a couple buy-in's is hurting your play, then you need to log off after loseing a couple...

eitherway, multitableing makes the swings hurt less, if I had been single tableing the night that my sig is about I would have had 4 or 5 negative days to write about, not just one quickly recovered from...

what do you think hurts your play more...

one bad day with a 1 day recovery, or 5 bad days with a 5 day recovery? .. over a week in the negative would be a lot more tilting than one bad day and back in the black the next night..

"Note to self: Let go of negative days, sleep is more important than ending the session up" <------ ?
exactly.