Maybe the workaround shared below should solve your issue:
In the survey tab of your xlsform:
In the settings tab of your xlsform:
Reference xlsform:
Time Difference.xls (32 KB)
Note: Using this approach, the enumerator need not enter the time. It get’s automatically entered by the system. The once used just below the time should allow you (as an admin) to keep a record if the enumerator has changed the time manually while collecting data. This is not seen/observed by the enumerator while collecting data.
