I don't personally know, but I look at these totals every year and the variability, at least when it comes to the Los Padres, is pretty much what you see every year. Based on that, I've always thought the totals were pretty accurate.
Yeah. Now that I look at Uncle Rico's map again, I believe it. The medium-hit areas (yellow in his map) are clearly clustered, and not distributed randomly. So they're displaying some real effect. Interesting!