The activation period is used to define the period of validity of a heading, in order, for example, to prepare new headings in advance.
The heading will only be taken into account for pay periods included in the activation period.
Examples:
- 01/01/02 - 31/12/02: the heading will be calculated only for the pay periods between 01/01/02 and 31/12/02
- 00/00/00 - 31/12/02: the heading will be calculated for the pay periods <= 31/12/02
- 01/01/02 - 00/00/00: the heading will be calculated for the pay periods >= 01/01/02
- 00/00/00 - 00/00/00: the heading will always be calculated.