I don’t know the answer to your question, but wanted to make sure you are aware of the discussion in

https://www.flyertalk.com/forum/cred...t-card-65.html

there seem to be some changes with regards to the fee for Amex and/or business cards. It isn’t clear to me what fee you’d actually have to pay, and I am not motivated enough to try or research further, so just dropping this in here in case you hadn’t seen those posts yet.