I harvested and washed some S-04 and pitched one jar into a blonde. It finished in 6 days at 1.002 (from 1.043). The yeast was originally pitched into an ESB. I pitched a Scottish export on top of the ESB yeast cake. I harvested that yeast, and pitched it into another Scottish Export. The current incarnation of this yeast came from the second Scottish Export, so this yeast has been around. Would this account for the 95% apparent attenuation?