Currently, this gadget gives average time between defined statuses by creation date. This does not allow a team to use this to track their cycle time for work completed during a specific week.
I do not think our teams are unique in that we our sprints are made up of issues.stories created at various times. Our teams would like to answer the question: "of the stories we chose to play this week, how quickly did we move between these defined statuses?"
To do that, he chart should be based on the time that the issue entered the target status. If the field is configured to track only the first time it entered the target status, then use the first time. If it is configured to use the last - or cumulative - then use the last time the issue entered target status.
I do not think that would be confusing for anyone, and, I suspect, is what many people assume is happening.
Thanks! Ben Friedman