You should be able to set a sprint End Time in the clickapp.
Its great being able to set start times and dates but for example I have a sprint that starts on a Tuesday at 10am and runs for 2 weeks. but when it rolls around to the end of the sprint mine ends on a Monday at 10am. which means I have a 24 hour void of tasks being worked on or closed and that really messes with the metrics.
I would expect that the previous sprint closes at 9:59am on the Tuesday and the new one starts at 10am.
This would be a great feature for anyone who has team members that close work off on the last day.