IBUs in recipe don't match - maybe a bug

I entered this over in the Beersmith-2 Questions page but got 0 replies.  Maybe it's a bug.

Putting together a Doppelbock partial mash recipe.  When I add 1 oz. CTZ for 60 minutes, the column %/IBU says 17.0 IBU.  But the bitterness (IBUs) in the style comparison says 27.4 ???

It looks like the %/IBU column calc thinks that the late extract additions are for the full boil?

attach the recipe so that we can see exactly what is happening.

Oginme said:

attach the recipe so that we can see exactly what is happening.

Click to expand...

Where do I find the recipe for attachment?

Click on the recipe in the folder where it is stored.  Then click 'file' >> 'Export Selected' and save it as a .bmx file.  You can then attach this to your next post to this thread.

We will then be able to open it up and see the recipe and your equipment/mash profiles to try and help you out.

OK, got it.
Notice that the IBUs in ingredients do not match the IBUs in bitterness.

The offset seems to be related to the late extract additions.  When I remove those or set them for a 60 minute addition, then the numbers converge to 16.8 IBU.  Since this is the value that the hops would give using a full 60 minute boil of the extracts, I am thinking that there is something in the calculation of the IBU contribution for the individual ingredients that is off.  I would go by the final calculation of IBU as shown in the style guide comparison which seems to be more reasonable, given the late extract additions.

Why the calculation for the individual hop is off is something for Brad to comment on.