When trying to figure out the ibu's in by beer using a calcualtor like the one here: http://www.rooftopbrew.net/ibu.php
I'm entering the times for each addition of hops as the total time that those hops spent in the kettle.
Is this the general consensus or should I enter the time that that specific addition spent in the kettle until the next addition of hops. I assume the formula is meant to use total time but started to doubt myself when my beers seemed to be less bitter than the ibu calculation said they should be.
Thanks in advance,