Just me personally but I've gotten to the point that my bittering hops are very interchangable..ie....I will just plug the most effecient (read high AA hop I can find) at the moment Northern Brewer in as my bittering hop...and then the flavor and aroma hops I follow the recipe or style guide as close as I can...the reason being that.
if you know what your total IBU's are supposed to be and you know what your flavor and aroma hops add...then you work backwards...ie...if you get a batch of Northern Brewer at 9 % AA then you set your recipe accordingly and set the right amount...but if your bittering hops are 14% of course you'll need less...and good software of course will tell you when your on target.
If that isnt clear pm me and I'll expand.
Please! This is supposed to be a happy occasion. Let's not bicker and argue over who killed who.