Free Usage time inconsistancy

[#1]

small prob:  I noticed that yesterday my Free Usage was listed as 0KB and I'm finding this a little strange as I turned my computer on earlier than usual to download a file before 8am. It was only the Firefox 2.0.0.6 update, a small 5 or 6mb file, but that download was initiated at approx. 7:51am and only took the usual short time to download. I know this as a fact.
This is a small and petty moan for sure but I am wondering what the situation is exactly if I ever need a larger file in the future?
Thanks in advance

[#2]

My understanding is any downloads started within 10 mins of a switch-over time are ignored. This is due to previous problems of incorrect classification / allocation of the download into the right time period.

[#3]

Yep, we get usage updates as interim packets every 20-30minutes or so.  To ensure that we don't overcharge or count free usage as paid for, we ignore certain packets that could overlap either period in the favour of the customer.
This could account for the small amount of usage that is missing.

[#4]

ahhh... Many Thanks.