When using QB time records, you're expected to calculate the time duration yourself and then enter it.
One way to not do this, to enter durations, us to use our BRC Timesheet Link
It supports several different time sheet layout styles, one where you can enter the start/stop times for multiple employees for a week:
Then, once completed, you can use the Timesheet Link to create an IIF file from it containing your time records for import directly into your company file into the time feature.