A good way to generalize this formula is that $ = Miles*(1+Cabin+Elite)/(AA Multiplier) as the max amount for a partner.
Cheers.
I did a check of the formula, it works. The only thing that it does not have is the amount of taxes if you book AA. So the formula above calculates the break even amount of the fare, without the taxes included (on an AA fare), which should be added to the break even amount from the current formula, to find the true break even amount of the fare. Unless I am missing something.