Originally Posted by
Vaze
The point is you can't book WT+ fares from AA.com
but in order to upgrade with AA miles the ticket must be booked at AA.com. See below
your original ticket must be booked directly with American Airlines (via Reservations or AA.com).
Whether you want to believe it or not, my understanding is correct, in order to buy a WT+ ticket it
must be booked at BA.com and can't be upgraded with AA SWU's or miles
By the way, I'm trying to help you so the snippy response wasn't warrented

Evidently WT+ fares can be booked by AA (albeit only over the phone) as the OP was offered the option to purchase a more expensive WT+ fare. The JBA upgrade scheme does not require purchase on AA.com, you even quoted where it says "Reservations."
AA certainly publishes WT+ fares. Without looking at specific dates, the cheapest o/w WT+ fare I see on FRA-WAS is W2E0 $2,021. The cheapest CW fare is IR5E6J which is only $1,628. My conclusion is the OP should purchase an I fare rather than trying to upgrade, unless there is a business travel policy that only allows purchase of WT+ and not CW.