If you read the article that had the recipe in Zymurgy, Vinnie said it tested at 95 IBU in the lab. A few years later Mitch Steele’s IPA book came out, and it tested at 65 IBUs in Stone’s lab. Other’s have said 65 IBUs in their Labs.
Russian River uses Hop extract for bittering, dialing it back is easy. Why would he do that? My guess is to make it easier to drink more. Many of the west coast IPAs seem less abrasive to me. Oh, I had a couple Plinys in the LA area last January, and they seemed less bitter than ~10 years ago.
I think the IBU wars are over, now it is the haze wars.
FWIW, the hop bill has changed over the year, while the grains and sugar addition has been pretty much constant.
Here is the hop bill from 2006.
Chinook leaf 13% 1.5 oz. Mash Hop (Yes, another old recipe, but it was Russian River’s at the time)
Warrior pellet 15.6% 2.75 oz. 90 min
Columbus leaf 14.3% 0.5 oz. 90 min
Simcoe pellet 12.0% 1 oz. 45 min
Cententiial leaf 9.1% 2.25 0 min
Simcoe pellet 12.0% 1 oz. 0 min
Columbus leaf 14.3% 1 oz. dry
Centennial leaf 9.1% 0.75 oz. dry
Simcoe leaf 12.0% 1.25 oz. dry
I have brewed this version a couple of times and loved it. Tried the newer 2012 recipe once, and did not like it as much - a little more dank than the original.
But it is awfully good. The only issue with the recipe is the amount of wort absorbed by the hops. As later recipes noted, I scaled up to 8 gallons, in order to collect 5. Wretched excess. But quite wonderful.