[BruceZ]

Why won't they?

It's a slippery slope.

You can't know that you are 1 SD above your true EV unless you know what your true EV is. If you've played so long that you know precisely what your true EV is to 1 SD of confidence, that means you've placed your EV in a range within +/- 1 SD where 1 SD has become a very small amount. If your actual win rate then moves 1 SD above this, at that point you cannot say that you are 1 SD above your true EV because the whole confidence interval for your EV shifted along with your results.

Another way to say it is that if you are 1 SD above something, that something is not an EV that you have any confidence in, by definition.

You can know that you are 1 SD above 1 bb/hr, but then are you a lucky 1 bb/hr winner, or are you actually a 1.5 bb/hr winner? If you are an X bb/hr winner, you can know that you are at least a Y bb/hr winner as long as Y < X. But you can't know that you are 1 SD above your true win rate of X bb/hr. You may be, but you can't know that because what you know is based on your confidence interval which is no longer centered on X.