Use Seniority Date for Absence Plan Accruals

Summary

Absence Plans Accrual

Content

I have setup the Seniority Date in the Derived Factors (Length Of Service) under 'Period Start Date Rule'.

And am trying to have the Absence Plan accruals consider the Seniority date instead of Hire Date (which was setup originally)

I have done this setup, yet the accruals are considering the Hire Date.

How can I configure this? And help would be appreciated

Thanks