This could be a separate issue, but I haven't been able to get info from the Data Usage tool in, oh probably, the last couple of months. I don't get any network or HTTP error - just the following message:
Your Data Usage Meter is undergoing maintenance and your usage may not be current. Please try again in 24 hours.
There is some usage shown in the bar graph, though I'm not convinced it's accurate. I'm not too worried about exceed my allocation, but I do like to check usage from time to time.