You could fit as many as you want. The 76 number on EL is irrelevant to AA's fleet. If you're asking how many could you fit in the current floorplan of AA's business class, well, the answer would certainly be "fewer seats than there are currently". That means fewer seats for upgrades, and on some flights it also could mean less revenue, unless AA believes it can get higher yields from its passengers. Less revenue is a big no-no. I don't know what AA's research concluded, but when CO did this work in the last few years, they found that their (corporate) customers were NOT willing to pay higher fares for full flat seats. Somehow, CO found a full flat solution that doesn't result in a loss of seats.