batch sizes? trub loss?
Remember that beersmith batch size is the volume INTO the fermenter.
I don't know what the Beer Alchemy definition of batch size is.
I don't know the BCS batch size, but normally JZ targets 6 gallons post-boil, 1/2 gallon trub loss, 5.5 gallon into fermenter.
I'm guessing somewhere in there is the cause of the difference.