Usage on first day of billing period included in previous month total

[#1]

I have noticed that the broadband usage in the first day of a new billing period is included in the summary total for the previous month.
Let me explain.
My line has been active for a while but I only got around to connecting the router on Friday 4th Nov at around 10pm or later.  The billing period ended at 00:00 on 5th Nov (or midnight on the 4th) so I incurred no overnight usage prior to that time but the summary shows 212.34MB.  When I could view the current month in detail it showed overnight usage as occuring on the 5th in the new billing period (which is when it was actually used) at the same time that it showed on the summary totals for the previous month.
So I conclude that the first day's broadband usage is included in both the current and previous month's usage summary, and therefore the usage calculations are incorrect.
Billing Period      Allowance Used Overnight Usage Total usage
05 Nov - 05 Dec    906.04MB        419.22MB                  1.33GB
05 Oct - 05 Nov      9.57MB            212.34MB                231.92MB
05 Sep - 05 Oct      0KB                0KB                            0KB

[#2]

The usage isn't reset at exactly midnight, that's why there is some showing for that date in both months. It's not possible to process everyone's usage at the same time so it runs through and resets them over the early hours of the morning but it's always in the free usage period.

[#3]

It sounds a bit flakey.  So there will always be a degree of duplication but only of the free allowance?.

[#4]

Nothing is duplicated. For example if the usage resets at 4am then any usage prior to that will be in last month, any usage after that will show in this month.