How to configure 90 days waiting period in qualification absence plan

Summary:

Hello Experts,

I have an Absence Plan (Qualification Plan) configured with:

• Plan Term Type: Calendar Year (Jan–Dec)
• Requirement: A specific subset of employees (identified through Bargaining Unit = 'ABC') should become eligible only after completing 90 days from Hire Date.
• For all other employees, standard eligibility should apply.

I have already implemented a Global Absence Plan Enrollment Start Date formula as below to start the enrollments after 90 days from the hire date. But looks like the formula is not working as expected and new hires are able to apply the absence from the start of hire date.

Appreciate if you could suggest how to implement vesting or waiting period in qualification absence plans? Also, how to debug the formula attached to a qualification absence plan?