I have an unlimited data contract with T-Mobile and they have been trying to get me to change contracts and save money for a few years now. Every time they ask me to change, I say 'no', they ask 'why', I say 'just because', they say 'you'd save money' and I say 'okay but I am still not interested'. This call keeps happening this way because I know that capped data tarrifs are a bit of a swizz.
For starters it's very difficult to find out how much mobile data you use 'on the spot'. You need to turn the data logging/tracking function on on your device and then see what you used 30 days later. At this point you have another, almost impossible hurdle to get over. The way they measure data ISN'T the same as the way you and I measure data. Once upon a time my wife purchased a 50MB/3 euro booster to use in Europe for email. That's email, not streaming audio or posting loads of selfies on Chavbook. Just text which is very efficient, but that said it's still outrageously expensive.
Me having been in the IT industry for years told her that 50MB would be plenty just for emails for a few days till we got home, but to turn data measurement on on her phone anyway...oh! and to make sure she turned data on when she needed it and off once she was done. You know how these greedy little apps leech your data in the background, eh! So very unexpectedly, two days later she ran out. Stunned, I asked to look at her phone so that I could check her data telemetry and she had only received around 10MB! Huh!? I scratched my head, double checked and triple checked, but no it was definitely well under 12MB so where was the discrepancy?
Now, I cannot confirm this theory but I am confident of it because all the pieces fit and if I were a CEO with stockholders I would be tempted to maximize profits in as complex a fashion as possible too. Bear with me here. All data communications require a protocol that both the sending medium and the recipient medium understand and use to verify things like the validity of the data. HTTP, FTP, TCP/IP, IPX etc, they are all just different protocols that are used for different purposes.
So protocols manage data transmission and different protocols do it in different ways, the overhead (that is the the control and management data that is sent along with YOUR data to allow the protocol to work correctly at either end) varies from protocol to protocol. In addition, the overhead will be greater for lots of small files and less for larger files. I don't know which protocol T-Mobile/EE for mobile data use but it would seem not be very efficient as they metered 50MB transmitted to our received 11MB. So T-Mobile/EE would appear to be measuring data INCLUDING protocol overhead in their pricing to customers as opposed to measuring what your device has received as usable data. Both highly misleading and very profitable. This is why if T-Mobile/EE never force me to switch tariffs, I never will. Unlimited data tariffs will never come back as we are set to consume and rely on it more and more. I could go on....best not.
I was looking to see if CAG was already on this issue. It would seem to be in it's infancy, but I will have to delve further.