This problem has existed for several versions because many times I’ve tried to clear my history using Settings > Clear History: All > Clear and found that the Usage statistics don’t change.
The Graph view shows that the data is cleared:
But the Usage view does not:
If you see my earlier post you’ll see when my usage past 1GB
The issue is a bit more complicated because the Graph views are also scaling incorrectly. I suppose that they may be using the usage data for scaling but only displaying the data after deletion or some strange combination of the same:
3 Hours 3MB
24 Hours 10MB