Also, normalize the grid times to round numbers instead of random.
We got it working. The left edge and the right edge should be "correct" and "truncated", the internal tick marks "truncate" their display value (so may or may not be exact - we may need to look at that).
We basically did the following. Based on the Time Interval, the nearest "truncated" time value for the LEFT EDGE truncate to the following and the right edge is then based on the Time Interval (you choose that; internal tick values will depend on number of tick marks configured and the chosen Time Interval)
(0, 10 seconds) - don't truncate (old way)
[10, 5 min) - truncate left edge to whole second
[5 min, 10 min) - truncate left edge to 10 second mark
[10 min, 30 min) - truncate left edge to 30 second mark
[30 min...) - truncate left edge to whole minute mark