Denny, my data shows that for low gravity beers, efficiency approaches 100% if you are crushing enough, which clearly, you are. I figure that gravity points plus efficiency points are almost constant for any brewer. Example: My average homebrew has a gravity of about 1.059, and my average efficiency is currently about 84%, plus or minus. So my constant is 59 + 84 = 143. Then I can use that to back-calculate what efficiency to expect for a 1.042 beer. The result is 143 - 42 = 101%! And in reality, this is damn close to being correct. In reality I would likely get around 96% or something like that. So I'm not at all surprised by your 99%, knowing that you and I both routinely get efficiencies in the low 90s if we want to.
Now if your beer turns out thin, watery, and lifeless, this would help prove my other theory that high efficiency is not such a good thing. I currently purposely would open my grain mill to shoot for an efficiency in the 80s because this requires more grain to be used to hit the same gravity, which results in more flavors from "grainy stuff" in the final beer. More experiments are needed to confirm. If this isn't the coolest experiment that's never been run yet, then I don't know what is.