The $75 same-day change fee is clearly waived, but delta.com leaves room for "applicable change fees" to be charged to GMs+ for same-day changes. Granted, I don't know if government taxes fall under "applicable change fees." That part could be open to interpretation, and explain why there are some inconsistencies when taxes are charged or waived.
https://www.delta.com/us/en/change-c...-flight-change
Originally Posted by delta.com
Diamond, Platinum and Gold Medallion Members:- Same-Day Change Fee* is waived — If the requested flight is Same-Day Confirmed eligible the fee will be waived.
- Applicable Change Fee — These fees vary based on your ticket and its applicable fare rules.