I just got a message from Fido that my data usage is over limit (1Gbt), however my phone counter is showing 73%. Nobody from customer service can tell me when and how I used my data -why? No customer ever asked that question before? You can show me day by day data usage on my bill and you can't see now what is going on? How do you know my data is over limit if you don't know where the number is coming from? Or is it just time game and two weeks later customer will not remember anyway, so let screw him up as soon as possible? I have paid for my data counter and if it is wrong I will ask them to pay my money back, if Fido is wrong, Fido will pay my money back. I will not let it go, promise.
Your phone is definitely a good way to help monitor your usage but as mentioned in most devices "carrier data accounting may differ from your phone". You also have to make sure the billing cycle matches what you have in your settings to make sure it resets at the same time. In terms of billing, you'll be charged for the data calculated on our end.