As things stand now, the ability to check the detailed usage of your plan is very primitive. It is better than nothing but it could be made so much more useful. I have a few "simple" suggestions for enhancement:
(1) Add another time period to the "7 day" / "30 day" drop down so that you can get the usage since your last payment (i.e. the start of the 30-day plan payment period.) Without this option, one has to check the billing history to find the most recent payment and then use the custom date range in the Usage History to find the items since that payment. The user shouldn't have to do this extra work.
(2) Add some very simple filtering options. For example, since the popular $15 plan only includes 100 minutes of outgoing calls, many people are likely more concerned with "Outgoing Call" usage entries. Another filtering option might be "only include entries which count against my plan limits" (e.g. only data usage and outgoing calls for the $15 plan and only data usage for the $25 unlimited talk plan.)
(3) Add a column in the usage details table to indicate which entries count against the limits of the user's plan (sort of an alternative to the second example of entry filtering in suggestion (2) above.
(4) Add an option to download all of the entries (rather than just viewing 15 entries at a time) in some format - Comma-separated values, tab-separated values, XLS/XLSX format. This would allow for for more advance filtering on the user's computer (e.g. using Excel or the like.)
