I've just taken a look at my latest O2 online bill.

I'm rather confused  at their GPRS billing.

I use my Nokia 6021 to check and download POP3 mail, several times a day, 6
days a week. I have 1meg of GPRS included in my tariff.

Why are some downloads in between batches of inclusive downloads showing as
chargeable, and then back to some more that show F  (included in tariff)..?

In other words, in any one billing period, I seem to have to pay for some
downloads, in between batches of inclusive ones. Most are only for 125k or
less....

It goes a little like this for example:

GPRS 25k F
GPRS 80k F
GPRS 75k 0.05p
GPRS 62k F

So, the third out of those 4 (in my highly simplified example would be
charged, the others either side not).

Si.