As the title would suggest, I've changed (increased) my data limit mid billing cycle. The support section of the AT&T website says that you're just changed your old rate for the part of the cycle that you were on that, and your new rate for the part of the cycle that you have that. That seems well and good, but my data limit has reset, which leads me to think there is going to be shenanigans on the bill. When I signed up for AT&T I had to pay a full month's bill for the first 3 days of service, so I have a bad feeling I'm going to be charged for two months worth of data (one at my new and one at my old rate).
Is the data limit resetting just a display bug/quirk of the website, and my usage hasn't actually been reset? The example given doesn't go over a data plan, just a voice plan, so I'm not sure if the given example necessarily applies.