I believe the "deception" comes from the fact that the beer tastes like chocolate and coffee, but there is no chocolate or coffee anywhere in the ingredients
What yeast did you use? That seems like pretty good attenuation to me. I doubt it was under-attenuated, so I am leaning toward infection. Have you actually tasted any of the brews? Does it taste right if you let the fizz die down? Any more info you can think of may be helpful.
I would probably do 2 ounces of willamette at 60 and add the fuggles in the last few minutes. That would get you into the 25 IBU neighborhood, which should be excellent for a porter.
I use a cloud-based brewing software available at www.brewersfriend.com.
They offer a free trial that will allow you to save up to 5 recipes, but I quickly realized that having brewing software was an excellent resource, so I paid $10 for a one-year membership.
I love the recipe builder...