CR calculation, deck height/effective dome volume?

YR, thanks for the reply. The formula I've always used is CR= SV+CCV+HGV+DHV+EDV divided by CCV+HGV+DHV+EDV. Since I've never had domed or above deck pistons, i've just ignored the EDV. The only Chrysler engine book I have is the old DC one, and it doesn't go into great detail about formulas, but it does refer to the 1/2 or 1" down method. I'm just not understanding how pushing the piston down .250", filling the cylinder, and subtracting a volume equal to the mathematical volume of area x 250" (Larry Shepard compares it to a "disc") isn't correct. Which lets me ignore the negative EDV number, at least in my case. Thankyou for your time and patience.