Well, without knowing the AAU of the hops, it'd just be a guess as to the bittering you got. But I'll still make a guess that you didn't have nearly enough malt for that many bittering hops. AAUs are hugely important- I have some amarillo hops that are 9.5% and some that are 4.5%. That makes a big difference in the amount of bittering compounds you'll extract.
That recipe is really not very good, so I'd suggest not getting any more recipes from that source. It's all bittering hops, too little base malt, too much honey malt, and too much honey. You only have about 60% base malt there, if my quick math is accurate.
Anyway, using my 9% AAU amarillos as a guide, I figure that you have IBUs of about over 50. That's not too much in a beer with an OG of 1.070ish like that recipe would provide, but you have NO flavor or aroma hops beyond that 20 minute addition, so you have plenty of bitterness but no hops added to balance it at all. Mashing at 150 and adding 3# of honey makes it even worse- a thin, dry, bitter mess of a beer.
I'm certain that in this case it's a bad recipe. The recipe is really terrible.