I'm sure they used more hops at 60 minutes than that. In addition, it wouldn't be a bad idea to throw some at FWH to give the beer a wonderful hop flavor to round out that bitterness. I find that when FWHd enough, high IBUs tend to be hidden amongst the canopy of hop flavor. Columbus is likely used quite a bit at bittering to get about 70 IBUs, and I'd say Simcoe and Warrior at FWH and FO, and Centennial and Chinook for a ton to flavor. I'd then probably dry hop with Simcoe, Columbus, and Centennial.
I also know that he uses a lot of hop extract....
I'm assuming the 20-30 min steep you were mentioning was a FWH addition? Good luck!