Well, the AI isn't calculating your RTS behavior, autocalc is just calculating the results of the fight base on what an average RTS player would get in terms of losses. If you want special strategy, play the fight yourself. At least that would make sense.
As for the percentages, as I said earlier, right now they seem to be indeed your chances to win or lose, so you should see your troops losing an 80-20 fight 1 times in 5.
But people seem to have issues with that, so it might be adjusted e.g. as I suggested in the other thread by giving you practically 100% win chance once you outnumber the enemy substantially and replacing the percentage to lose a fight with a percentage to suffer losses.
Anyway the latest patch has adjusted something about the autoresolve, I think, so we might first want to see how it plays now.
