Beersmith2 has an option for steep/whirlpool, which calulates the ibus depending on time of whirlpool/steep. But is doesn't adjust the boil additions accordingly, as in by adding a 15min hop stand, a 10min boil addition pretty much becomes a 25min addition, IBU wise. Thats why my 25 min addition in reality will be going in with 10min of the boil remaining.
I agree with Parks, I have found my less bitter beers seem more bitter after dry hopping, but most crap you read on the net states that dry hopping adds no bitterness..