You can enter in data for a previous date, even though the end date is not something that you can directly update.

It is a little confusing we realize and eventually we'll just provide a way to directly update the end date, but in the mean time here is how you can do it.

Set the start date, start time and end time and the app will automatically set the correct end date for you!  It does that because the app assumes that no data entry is ever longer than 24 hours.