I found C inventory on some PHL-BCN and BCN-PHL flights this Summer. A main cabin fare priced at $1695, but in the details it shows it goes into "Q" fare bucket which isn't eligible for a BXP3 cert. $2125 PE booking will qualify. J will be $3941. I guess the only way to find something in between $1595 and $2125 is to put the $1595 Q fare on hold and call to ask about up-faring to an eligible fare that will still be under $2125. Trying to break it up as 2 one-way fares is significantly more than a RT, too.
With maybe 5-10 minutes of learning curve, you can fashion a search on ITA Matrix that excludes B/N/O/Q/S fares and gives you the lowest resulting coach fare. (
https://matrix.itasoftware.com/ -- but google around for bloggers' tutorials on how to use the routing & extension codes correctly)
You can then use bookwithmatrix.com to copy-paste the full resulting itinerary page and click through to book on AA.com
Also that seems high for coach flights, but I guess that's the price you pay for nonstop on a monopoly route... looks 2-3x the price of nonstops out of JFK.