I have raised tow tickets on the usage stats recently. This relates to PAYG, in case other types of account have different stats.
First I queried the "usage this month" figure, which is NOT a total of the day-by-day figures. I was told this is because it is "usage this calander month". This, of course, is really STUPID as PlusNet point users to this figure so they can guage how they are performing against their pre-paid bandwidth allowance.
The I queried an email I had received saying I had exceeded my pre-paid bandwidth and had incurred an extra cost. At that point I was still 0.5Gb below my pre-paid bandwidth, but had exceeded that amount in the calander month. I asked if the bandwidth usage was calculated on a calander or billing month. Answer - billing month.
So, PlusNet are guiding people to a stats page, then giving them the wrong information. Further, they are informing their customers they have incurred extra cost when they have not. Do they plan to change this? "Thanks for your feedback. There are no plans to change this at this stage, but we may improve the system in the future based on customer feedback". It beggars belief.