Accrual Plan enrollment end date formula to identify back dated changes to eligibility

Summary:

We are trying to automate the movement of people to different accrual plans when eligibility changes.....but when those changes are backdated.

Content (required):

We have developed an enrollment start date formula which is handling the enrollment start date (including for back dated changes). This is working fine.

We are looking for advice and help as to how we can use an enrollment end date formula to processes the loss of eligibility for when people move plans. Our HCM data is loaded to cloud via interface from an external system so we are not in control of what changes come over and when. Currently we run the update accrual plan enrollments process every day with the date parameter set to sysdate.