I saw the same thing in Recipe View, and then checked my custom text report which shows Pre-Boil and Est OG.
10 minute boil = Est Pre_Boil Gravity: 1.051 Est OG: 1.063 SG
90 minute boil = Est Pre_Boil Gravity: 1.060 Est OG: 1.063 SG
I presume BSmith works on the assumption that you'll hit your OG target, and puts the burden on collecting enough gravity to make it, even with a very short boil.
However, I don't see the compensation factor in "more grain" or "higher EE%" needed to account for the higher gravity needed.
Anyone see where the lack of "boil down concentration" is made up for in another input?
:-\