Buzz's range is consistent with what I have read. Tom Lehmann, in his deep-dish dough recipe in the PMQ.com recipe bank, calls for 3-5%, but I have seen him recommend 7% when butter or Crisco is used (plus oil in the pan). He has also said that he has seen as high as 15% and 20% butter/Crisco in some dough recipes.
I recently saw a couple of Pat Bruno deep-dish recipes (I can hear Buzz groaning now) with 16% (in a pizzatoday.com recipe) and 10%. I estimate from an Emeril's deep-dish dough recipe I saw recently that he uses 22%. A deep-dish dough recipe I found at ivillage.com uses 24% by my estimation. DKM's deep-dish dough recipe on the recipe page of the forum calls for 19.3%. Recently, our members, including me, have been testing the outer limits of the 10-25% range mentioned by Buzz.