Vodafone have an issue

I was interested as to whether Vodafone's data recording was any good. So I awaited my first bill on an iPhone plan.

This is the data section

It says that as at 7th Jun I had used 57.4Mb.

BUT...


On my phone as at the 9th June (two days later) the cellular data counter says 9.2 out and 43.3 in. So two days later I had used 52.5Mb according to my phones counter. Note I have never reset the counter!!!!

That is 4.9Mb different which doesn't seem a lot. However that is a 9% difference.

Sooo... who is right??? My Apple iPhone's counter or Vodafone's systems.

I think I shall e-mail Vodafone and ask.