How accurate is the usage monitor

[#1]

Hello all,
I am curious as to how accurate the plusnet usage monitor is, I have been live since the 10th of this month between then and now i have apparently used 10Gb. The only device i have connected to my plusnet router is my ipad and neither the wife or i have used it much most definitely not 10Gb worth. According to the monitor over 80% is streaming which is about what... 3 to 4 hours of SD content on iplayer or youtube, i know for a fact we have not done that much. which is why i thought i would ask if anyone else has had similar issues.
My routers wifi is secure and apart from the ipad nothing else seems to be connected so i am confident my adsl isn't being jacked. Before getting plusnet i had and still have  a talktalk adsl line which although was a 40Gb limit we never went over 5Gb/month however based on my first week with plusnet i am looking at 10Gb/ week Both my plusnet and TT lines are connecting at the same speed so its not a case of being able to do more on the plusnet line because its faster... because they are the same.
Any thoughts appreciated.
Stephen

[#2]

The usage data is very accurate.
Looking at your usage on your account and breaking out per hour in the day for the 14th (we can do this internally), we can see that the usage is consistent with peak time use of the service and not spread in a way that I don't believe it is background use of the service whilst you are out of the house.
Specific to the 14th, there was 0.44GB used between 6 and 7am, then the rest of the usage spread between 5pm to a little after 9pm. All other hours are under 1MB, which is typical of standard background data when leaving your connection on.