Hmmm... I looked at the recipe, but there's no hop additions between 30 minutes to flameout. I'd think you'd want to add some hops at 20, 15, or 10 to get flavor. The Sculpin certainly has flavor.
I don't add hops to IIPA between 60 and flameout and the beer never get's criticized for lacking hop flavor. It has won a lot of medals including an NHC Gold as a fruit beer.
Hop flavor is bitterness (sensed on the tongue) and volatile aromatic compounds sensed retro-nasally. So if you get bitterness and you get aroma, you then have flavor by default.
Not saying there is no point in adding hops at 15 minutes, just that the idea that flavor uniquely comes from those additions is flawed and that I have personal experience with making beers with big hop flavor this way.
I've seen that recipe before and have every reason to believe Sculpin is made that way and, yes, it does have a lot of hop flavor.