I don't know. I've been checking overnight this summer because one day is so different from the next (and because my daughter asked me to) and I'm not really seeing the value, possibly because of our personal situation (MDI, 5 months past diagnosis, not in the throws of puberty, etc).
In roughly 75 days of testing, I've seen three potentially actionable numbers. One was a low in the 70's, one was a 280+ high and one was a low 100 number that I had her drink juice for because I knew she planned on sleeping in.
Otherwise it's just an "ok, here's the number" and I do nothing with it. It might be a little high, but not worth it to correct it since (a) we're on MDI and (b), her correction factor is a moving target and I'd probably under-correct to ensure she didn't go low.
As it stands, when school starts, I'm going to discontinue the checks and only check on nights when I think it's necessary.
DD diagnosed March, 2013 at age 10, now 11 years old
T:slim (Humalog) as of August, 2013
Dexcom G4 as of November, 2013