Apologies in advance for the basic question: I'm flying TBS>IST>ATL on an X class ticket in late April. Right now, I have the opportunity to upgrade to business for 45000 miles for the IST>ATL leg, but I'd need to buy the miles outright. Is there any chance that the miles needed will decrease for this class or that I could possible pay less if I try to upgrade at the gate (though I'm not certain I'd even be able to do that on an X class reservation)? Or is 45 k the normal upgrade fee on this route? Thanks for the help!