If you have configured users with Locked In-Out Timesheet, then Web TimeSheet will automatically punch out the users at 11:59 PM, for it to calculate the actual time for that particular day( 12:00 AM to 11:59 PM). However, it will automatically punch back in at 12:00 AM.

Note:
It will automatically punch out at 11:59:59 PM and punch in at 12:00:00 AM, so when you run a report for the time entered for that user, it will be accurate and not show the difference of the one second.