Significance of Date Validation Settings for Initiative

Hi,

We are unable to get the significance of below settings which are present in install mode

Navigate to Administration --> Initiative settings -->Date Validation settings --> Top Level Activity

1) Allow close date of previous Top Level Activity to be greater than close date of next top level activity

2) Allow close date of previous Top Level Activity to be greater than start date of next top level activity

For non phase gated road map, even though this setting is enabled/disabled, it is making no difference.

Please let us know the significance of these options in both phase gated and non phase gated road maps.