When your data went from 80 to 46% two days ago, could you post screen captures of your McAfee history log during that time. It may take more than one screen shot to cover the period unless you can make a .pdf print of it. That should show what was coming in and going out during that time.
Double click the McAfee icon in the task bar or on desktop and select all history.
I only used McAfee when it is pre-installed on a new computer until the time runs out, but that is the way it worked for me. Check the above site to see how to do it and use the other features. You could also look in Help.
Go back in time to the incident the other day and also look at why you lost data allowance today while at work.
Your screen captures are a bit small for my old eyes but Charles McCool appears to see them ok. If you can make a .pdf of the list then the text size is easily enlarged.
Photo captures in .png or .jpg do not enlarge well.