I never went through with it, but what I was told was that A was sold out, but F was still available, and the only way to get that was through a rebooking (at an exorbitant cost). Five of six agents said that if I purchased the upgrade it would not increase my status miles for that segment...so maybe the question that I should have asked was would it change the booking code vs. being an EMD. Next time I'm in that situation, I'll specifically discuss the booking code for the cash upgrade to make sure it's not just an EMD via phone purchase.