Again, I don't claim any special knowledge to the brewer's true hopping schedule, but I believe my recommendation still satisfies his description. He did emphasize Liberty, but didn't specify whether that's for bittering or aroma or both. If, for instance, you bought 1 oz Liberty (not just the 1/2 oz I called for) you could do something like this, also dialing back the Chinook a little to pacify
Barley Water 
Note, Chinook was by far our highest alpha-acid percentage, so I switched to a 90 minute boil to increase extraction of the others:
Bittering hops: .5 oz = 14.2 g,
Chinook, 90 minutes
Bittering hops: .5 oz = 14.2 g,
Liberty, 90 minutes
Flavor hops: 1 oz = 28.3 g,
Willamette, 45 minutes
Aroma hops: .5 oz = 14.2 g,
Liberty, 10 minutes
Aroma hops: .5 oz = 14.2 g,
Cascade, at flame-out
Aroma hops : 1 oz = 28.3 g,
Chinook, dry-hops added to secondary fermentor one week before bottling/kegging
There are a million different combinations you could try. Regardless, I think you're going to end up with a really tasty American aroma IPA.