How to Prorate HSA Maximum Election Amount Based on Coverage Start Date During Enrollment?

We are looking for guidance on how to configure a prorated HSA maximum election amount for employees whose coverage start date falls between January and June.

Current Setup

HSA is configured as a coverage, and we use variable coverages based on an employee's pay year type (i.e., the number of months an employee works — 4 months, 12 months, or between 4 and 12 months). This structure exists because the maximum HSA election amount varies depending on how many months an employee works. The eligibility profiles tied to each variable coverage are based on two criteria: the employee's pay year type and the employee's age.