I've searched all of the Delta Reserve threads in this forum and read the Amex T&C and cannot figure out the answer to this question:

Does anyone know the timing of the $175 Delta Amex Reserve Authorized user fee? Is it on a calendar year basis (i.e., if I add an authorized user in May 2025, will I have to pay the Authorized User fee again in January 2026)? Is it the same as my renewal date (i.e., if my card renews in March 2025 and I add an authorized user in May 2025, will I have to pay the authorized user fee again on my renewal date of March 2026)? Or is it set on its own 1-year calendar such that the Authorized User annual fee renewal is 1 year after the Authorized User was first added (i.e., if I add the Authorized User in May 2025, I would have to pay the fee again in May 2026, independent of my own renewal date fee)?

As context, the person who I want to add is not traveling on Delta until later in the year, and I'm trying to figure out if there is any benefit or cost to adding them now versus adding them later?