Your entries in the block Period are only used to determine the time period, not to select personnel numbers.
The indicators Today, Current month, Current year, Up to today, From today, and Other period enable you to determine the data selection period from which the employee data is selected.
Sometimes, the field Employee selection period is also available. If you specify an employee selection period, only those personnel numbers are selected for which a valid record exists for infotype 0001 Organizational assignment on at least one day in the specified period. This enables you to ensure that only employees are selected who were employed at your company on at least one day in the specified period.