After some testing this is what i found out.
Work Period for today (14th 5pm to 15th 2am)
Work Period Report for "Today" shows total of the above Work Period
Work Period Report for "Yesterday" also shows total of above Work Period.
To get the Work Period Report of Yesterday (13th 5pm to 14th 2am)
Work Period Report Date Period 13th to 14th has to be selected.
Is there a possibility of adding a little easier date selector for touchscreens. its very hard using a touchscreen.