Adjustment Calendar Not Calculating Based on Session Start Date

Our adjustment calendar for student drop currently uses Session Start Date as adjustment option. For spring term, regular session, the session start date is Jan 08, 2024. A student should receive 100% refund up to 16 days after the session starts, and 0% refund after the 17th day.

It is working for normal scenarios. However, we have few students that registered after the first day of the session (Example: Enroll Add Date of 01/15/2024). One of these students dropped on 01/26/2024 but the Tuition Calc is still issuing 100% refund.

We are expecting that since it is past the 16 days, tuition calc should not refund any money anymore. I played with the data in our non-production database - if the drop date is set to 01/27 or earlier, a 100% refund is issued; and if the drop date is on or after 01/28, a 0% refund is issued.