Absence Entry Validation formula failed to restrict gap between Parental Leave and Sick Leave

Hello Experts,

We have the requirement that "After parental leave, 4 weeks of work are required before self-certification sick leave can be used" and to achieve this the following logic is applied. But the entry validation is not working and sick leave is getting submitted after Parental leave

/*==========================================================
FORMULA TYPE: Global Absence Entry Validation
============================================================*/

DEFAULT FOR IV_START_DATE IS '4712/12/31' (date)
DEFAULT FOR IV_END_DATE IS '4712/12/31' (date)
DEFAULT FOR IV_TOTALDURATION IS 0
DEFAULT FOR PER_ASG_START_DATE IS '4712/12/31' (date)
DEFAULT FOR ANC_ABS_ENTRS_DURATION IS 0
DEFAULT FOR ANC_ABS_TYP_NAME IS ' '