The problem is that even if you would get a hold of the exact loot formula, it won't do you any good as far as your return goes cause there is no doubt a couple of random elements in it. If there weren't then loot would be a fixed outcome and you would get the same return everytime you kill creature x with weapon y.
Back in the days of the commodore amiga i made a jackpot game to play with 2 friends of mine. It had a twist in that you could play 5 minutes each and your score would be kept on a scoreboard. After 5 rounds of 5 minutes each we paid the difference to eachother to add some excitement to it.
And guess what?
Eventhough i knew exactly how the formulas were since i programmed it, i still could not predict the outcome. I lost/won about as many times as my mates did over time. Ain't randomness a beautiful thing?
And for those of you that are now gonna say a computer isn't truly random cause the random number is based on a seed... you're right. But for us it IS random, cause there is no way you can predict the number sequence, especially not when the seed is something like the time passed between hitting key x and key y, or whatever else timebased seed. Or combined time based seeds etc.
If you can't predict the outcome, it's random. If the loot formula has random elements (and it HAS to have them), then you can't predict it.
There's no doubt some areas are "hotter" than others at times, where the return is better than average. But you can't predict that area cause well uhm... they are random
Even the time it lasts is random.
The best you can do is observe where people loot good and hope for the best.
In short: even if MA would hand over the formula you won't be able to predict what to do because of the random elements.