For home brewers, maybe even commercial, I think we'd be better served to use which ever calculation we choose (sticking with one) and then when someone who is sampling the beer wants to know "how many IBUs" don't use numbers, just say low or medium low, or high, or very high, or whatever term best describes it. Or take the time to explain what is behind those pesky IBU numbers... good conversation piece.
On the other hand, telling them "47 IBUs" and hearing them say "hmmm, tastes more like 45 to me" tells you a lot about them lol