There is a reporting issue when using Timesheet Period as a filer option. This filter will allow you to select either:-
1. Timesheet period OR
2. Start date and an end date
The confusion arises when only one week is selected and the start or end date is NOT the start or end date of a timesheet period. This can cause data to be missing from reports unknowingly of the wrong day is selected.
It makes more sense for the range to be Select Start Period and Select End Period where the user can select the start timesheet period and the end timesheet period. No data will then be lost.