httpss://www.experimentalbrew.com/experiments/writeups/ibu-lie-kind
big take away is:
"Learn what 15 IBUs, 30 IBUs, 50 IBUS, 70 IBUS from your favorite calculation means to your tastebuds when brewed on your equipment. Use those landmarks to hit what you want to taste. That’s the only value to the number, because frankly, the number itself is fairly taste-free."
I have to agree with that. While I think about IBU's when I come up with a recipe I am normally coming up with the amounts by past experience. My spreadsheet does calculate the IBU number but I know it is not correct for anything after the boil. I always thought too much was put into how many IBUs a beer has and I am glad that at least up here in New England that philosophy is going away.