My point is that 8:2 isn't much better. Not compared to the range of skills available. If someone beats me 8:2, that puts fairly strong bounds on their skill level, such that most players would either beat both of us or lose to both of us.

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.