Another way to look at it, if Ke beats Lee 8:2 then Lee-plus-four-stones probably beats Ke more than half the time. (I'm pretty confident about four stones; I suspect two or three would suffice.) Four stones is significant, but it's still a fairly narrow gap to say "I think AG falls within this skill range" until you've seen it lose a game.
Games at this level are decided by a few points. The closer two players come to optimal play, the harder it is to be very much more efficient than your opponent over the course of a game. To be so much more efficient, at this level, that you could overcome a 4 stone handicap is unthinkable.
I would very much like to see computers improve to the level that they could take on a top professional giving a 2 stone handicap. That would be a sight!