So in addition to checking on ExpertFlyer, if you log in to AA.com, it will usually show you flights you can immediately clear a SWU on if you do a search on the website.

However, this evening I looked at some GRU flights departing within the next 4 hours. For example, I looked at JFK-GRU AA 951, which has an upgrade list of 4, two unassigned seats in J, and EF is showing C0. Yet, the AA website is showing "Systemwide Upgrade>" next to this flight and the DFW flight even though there's clearly more people on the wait list than available J seats. (BTW, interestingly enough, LAX-GRU has 0 people on the wait list, 4 seats unassigned in J, but is NOT showing "Systemwide Upgrade>".)

Does this mean that the AA website is just completely useless for checking SWU availability? I always thought that the SWU indicator was based off of C availability. I guess I'd be pretty upset if I paid for the ticket thinking my SWU would immediately clear based on the AA website only to be told no availability...