Usage depleted overnight. All updates set during free time.

When my status meter is full, it says 500 MB.  If i use less that 50% it rolls over to 100%.  If I use more that 50% it goes up 50% plus the left over from the day before. If there is nothing left over, I start the day with 50% which is 250 MB
Not sure how to do the McAfee history log.  I will check it out later.  I'm out of time for now.