OK, well I'd expect that if the eyebrow/notch volume is being deduced from the down-fill method, then some of that volume is actually from the crevice volume down by the top of the piston. That usually works out to 1-1.5 cc in the size range of these bores. I add that to the published eyebrow volume (or reduce the net dome-eyebrow volume for a domed piston) to account for that. Pretty much the same end result either way.