It's 20K miles plus $550 for either ticket. That being said, unless "R" classs is available AT THE TIME OF PURCHASE, a "T" fare may not clear as easily or quickly as a "W" fare, if at all. So, in any case, buy the "T" fare. You will have to pay the miles and upgrade charge now, but you will get it back if you are not upgraded. A "W" fare is more useful if you have GPUs, but even then, you have to play the lottery if "R" seats are not available.

Billy