I guess that could potentially be an option, something that is recalculated and updated during the automatic clean up. Right now, the start and end dates are saved in the sheet table after dates have been set, and are mainly used to filter and sort sheets. Also, even though the start date has passed, some users still want to see the original start date. So, if I add that as a feature at some point in the future, it would need to be an option that could be turned on/off.