Thank you JJEFFREY and nyc10036. The AA advisory supports your conclusions. I will pull the trigger and book a PE ticket on BA using AA metal. The price on BA.com is cheaper, plus I get the AARP and Visa discounts if I purchase on ba.com. The only drawback is that I wont enjoy the complementary or systemwide upgrades [I'm an AA ExPlat] on AA metal. My calculations revealed that, assuming our conclusions are correct, I'll earn more that twice as many loyalty points if I book on ba.com.

eg. ticket on AA.com costs approximately $1100 minus taxes = $900 x 11 = 9900 loyalty points.

Similar ticket on ba.com costs approximately $970, books in fare code T which gets 100% of base miles mutllied by EXPlat bonus of 120%. Distance for trip both ways total approx. 12000 miles. 12000 x 120% = 14,400 + 12000 = 26400 loyalty points.