If production start time is before noon, we simplify this to the current day. If production start time is after noon, we simplify this to the next day.
e.g. If production start time is 23:00, this means that Monday's production day starts on Sunday at 23:00.
e.g. If production start time is 06:00, this means that Monday's production day starts on Monday at 06:00.
This is why you may see a difference in reports.
Production Summary vs. Production Trend Report
Both use the Start time as found in the Production Module (23:00hrs). 23:00 is the actual start of the technical day, i.e. Sep 21st at 11:00pm. But in this case, there is really only one hour of data for that actual "day" before the date changes to Sep 22nd. The Production Summary reports uses the "technical" date to display the data. The Trend Report, on the other hand, pulls the production data from the actual production run day, i.e. all of the parts that were run during that "day" Sep 22nd.