A few UI issues in the Android app version 3.0.360r:
When a data plan has been created, the app doesn’t show the correct end date for the plan. I think it is always showing one day extra. For example, if I create a custom 30 day plan starting on Mar 1, that should include the dates to Mar 1 - Mar 30. The app shows 1 Mar - 31 Mar, both in the data plan screen, and when viewing the data plan in the usage screen. Monthly and weekly plans have the same behavior, showing an extra day at the end. This is confusing and makes it difficult to match the exact data plan time period. The end date shown for a plan should be the last day that is included in the current time period, not the first day of the next time period.
Somewhat related to the above, the data usage screen shows the vertical usage bars between the dates on the horizontal axis instead of aligned with the dates, and therefore it also shows an extra day past the end of the plan. That makes it confusing to know which bar goes with which date. For example, select the “Week” display option. The bottom axis then show 8 highlighted dates, and usage bars are positioned between the dates. In that example, I think it would be much clearer to highlight 7 dates on the bottom axis and position the usage bars directly above the corresponding dates. The same comment applies to all the views except "Day. The Day view seems logical as is, since the bars represent 3 hour time periods, so it makes sense to position the usage bars between the boundaries.
The 3-dot overflow menu for a data plan in the Data Plans screen has options to “Edit Counter” and “Delete Counter”. It would be clearer and more consistent to use the term “Data Plan” in those menu options instead of “Counter”.
When the “Delete Counter” option is selected for a data plan, the plan is deleted immediately. A confirmation dialog should be displayed to avoid accidental deletion.