I'm posting this so that someone with a similar problem might find the answer.
I have satellite Internet which has a "free period" (i.e, doesn't count against data quota) from 3AM to 8AM. Some time ago I set up a schedule in Networx to reflect this. Recently I checked the reports and found zero usage in off-peak times. Huh? I know that I have downloads in the "free" period.
Looking at the schedule I set up, I had listed these times as "unmetered", not "off-peak".
Moral of the story: if you want reporting in the "free" period, you need to set the time as off-peak, not unmetered, regardless of the terminology used by your ISP.