I may be hijacking the OP's thread, but I think it's a very similar issue. Attached recipe and screenshots.
First screenshot I've got the mash-out set to 2.5 gallons, and secondary sparge step calculates out to 3.92 gallons. It's quite a bit too much water, I think.
Second screenshot, I adjust the mash-out to 2.9 gallons, and calculated secondary batch addition drops to 1.92 gallons.
Interestingly, if I adjust in increments, (2.6, 2.7, 2.8) the secondary step always stays the same at 3.92 until it flips down to 1.92.
I use a custom batch sparge profile too.
OS X Mountain Lion (observed same behavior on Lion), Beersmith 2.1.02