Beer Captured Recipes - incorrect IBUS?

Does anyone use these recipes and have you noticed the IBUs seem fishy? Example:

Cream Stout (pg 113).

10 oz Crystal 60
8 oz US chocolate
6 oz Roasted Barley british
4.5 lb LDME
1 lb Wheat dry extract
1 lb maltodextrin

1 oz Kent Goldings 5% AA at 60 min
.5 oz fuggles 4.8% AA at 60 min

.25 oz kent goldings at 15 min

The books uses extract recipes, this one calls for an initial (partial) boil volume of 2.5 gallons. The recipe states that the IBUs should be 26. This would be true if it were a full boil. But with the partial, you would fall far short of that. Beersmith gives me around 14, and my own calculations using How to Brew confirm this. I've looked at one other recipe (biere de Garde) from this book and it's the same discrepancy.

The book does contain all grain versions, here they say to use 22% less hops than the extract recipe, so that would be wrong too.

Am I missing something? I am still learning and this is confusing the me.

 

I used my own numbers for the biere de garde in the book which I brewed. I wanted to do a late extract addition and that is how I ended up realizing that I thought their numbers were wrong.

It just seems odd that the authors would get something that basic wrong, and that there is no mention of it when I do a google search or look at reviews of the book. I can't be the only one that's seen it so was hoping for someone to confirm it for me.

 

I just discovered that if I switch the IBU formula in Beersmith to Rager, I get the IBUs from the book. So I suppose that explains it. Beersmith uses Tinseth as default and that is what how to brew uses too so that's why those two checks agreed.

I didn't even realize there were different formulas, so that just got more complicated for me.

 

Great thank you for checking that for me.