What is "Treat In/Out Time before Check Out Cut Off Hour as last days' attendance records when import"?

In Attendance Module Setup, General tab, Attendance Import Panel, when this option is turned on,

And the Out Time Cut-Off Hour in Shift Code or Global Working Hours, other settings tab is defined.

During Attendance Import, any time before that Out Time Cut-Off Hour will be treated as previous day attendance,

e.g. 2017/05/07  03:15 will be treated as 2017/05/06 27:15

Which is good for the overnight shift. So that the check-out time counted to the last work day.