Usage report anomaly

[#1]

This evening I logged into the Member Centre to get screenshots of my usage for the last month, which I tend to check most days anyway.  The month had ended yesterday, so I was unable to get a breakdown of that.  But I was surprised by the total usage shown for today at 20:56, 330MB, which seemed well over the top for what I had been doing, which was mainly viewing static web pages, with Flash disabled, and a couple of minutes of a Youtube video.  It had jumped  to 363 MB at 21:03, and to 400 MB at 21:08 - though some of those jumps may well have been due to the fact that the total is only updated sporadically.
My main worry is that on checking today's usage breakdown, 189MB of it is allocated to Gaming, which I don't do at all.  That figure has been static since 21:03. The 211 MB residue tallies well with both the download recorded for today by NetMeter and my own expectations.  I'm running W7, as a user w/o admin privileges, on an ethernet connection to the master socket, with modem wireless disabled.  I can't see any obvious incursions listed within Task Manager.  The only processes using more than 1 minute of CPU time are, in descending order, Firefox.exe, crss.exe, explorer.exe, TotalRecorder.exe, NokiaSuite.exe and vprot.exe.  I've not noticed anything like this previously; and haven't done any recent installations of any software.  I'm running AVG free edition and Windows firewall (which I realise by default is blocking only incoming.)  My modem log shows nothing amiss: one sole ICMP probe blocked by its firewall
So, any suggestions as to what's caused the Gaming part of the total: accounting errors at the PN end, external highjacking of the line, malware, ...?  And what's the next total update going to show?  Does the PN Gaming Total include both up and download traffic?  I assume so.  My NetMeter shows only 30MB upload during today, so the anomaly remains anyway.

[#2]

Well, the Gaming figure remains at the 189 MB of last Saturday, so it looks likes a one-off.  I've searched the forum and found other reports of such anomalies, at least some of which have been clearly attributed to the Plusnet  accounting systems.  That remains my main suspicion.  After a fair bit of checking and scanning of my own system, I've not found any likely cause there.
I'd hoped that someone from Plusnet might have had something to say.  The threads about similar problems have turned up in a variety of sections, and not predominantly this one, so maybe that's why.  I'm on an unlimited  package so am not worried about charges. But it is disconcerting, and takes up some time, when any unexplained behaviour occurs.  I think I saw in one thread that PN were able to produce an hourly traffic breakdown, by type.  I'd certainly be interested to see one for last Saturday, for cross checking against my local logs.  Any possibility of getting any more detail of the alleged gaming activity - such as allocation range of the remote IP address(es), port number used, and traffic direction?  Or can it be more or less taken for granted that the gaming traffic figure didn't relate at all  to anything done on my own system?

[#3]

Sorry for not replying.
The total volume of traffic is generally very accurate, however sometimes types of traffic can be attributed incorrectly. This isn't something I'd worry too much about.

Quote

I think I saw in one thread that PN were able to produce an hourly traffic breakdown, by type.

We can do an hourly breakdown showing upload/download but not by type of traffic unfortunately.