thanks, I will get Schlesingers book in due course, but..I don't understand your statement.
By definition the win rate is your expectation, given a certain playing & betting strategy ? What do you mean "outperform" ?
Used to compare games on like terms. The playing and betting strategies are held constant to get a good comparison. You can outperfom the win rate suggested by DI on some games by being able to tweak your betting to more optimal levels, use more playing indexes, get heads up play, better count systems, etc.