It's pretty simple. There are a fixed number of boxes for the histogram - it always consumes that number of boxes.
Divide by # of boxes
And you get your buckets
The goal was to keep it looking consistent and useful. You CAN zoom in to a section or refine the time period, but that's how the histogram works.
Thanks, Nicole. It has been bugging me. It has been a point of contention with my client this week as he feels it should be broken down into something that makes more sense to them. Thanks again!