Data base item to calculate absence accrual

Summary:

Content (required):

We need to calculate absence accrual for absence plan based on fast formula Global Absence Accrual Matrix. Accrual depends on length of service. We cannot use enterprise start date or hire date and we need to use seniority start dates (in some cases they were manually changed and they can be earlier than enterprise start date).

Can you please recommend us which data base item should be used to determine this seniority start date?

Version (include the version you are using, if applicable):

22B

Code Snippet (add any code snippets that support your topic, if applicable):