Pliny the elder clone

I have this clone recipe http://beerdujour.com/recipes/1pliny%20the%20elder%20clone%20pdf.pdf. It shows the IBU as being 95. When I build it in Beersmith 2 it comes up much higher is there something I am doing wrong?

For one, you can't match theirs.  Theirs is measured and BS2 is a  calculation that gets less accurate the higher the IBU.  When you calculate, you need to use some mathematical model.  All of the models are guidelines.  In cases where I have seen calculations compared to those measured by gas chromatography showed the calculation is always higher than measured.

In this recipe, adjust the hop quantities to match the alpha acid units.  If you know your system and know that your beers are always more or less bitter than the recipe indicates, you will want to adjust for that too.