in both cases the ball 10 elastically deforms to equalize ball pressure through the annular space 202 and the ball goes right back to its spherical shape once equalization of pressure takes place this is to be contrasted with the downhole oriented pressure differential situation of fig1 where leakage continued as equalization did not happen and the ball 10 distorted under the differential as indicated by lines 214 and leakage continued as long as the differential pressure on ball 10 existed in another aspect of the present invention it was noticed that in very deep settings of the valve assembly shown in fig1 9 the annular piston 26 was subject to such high differential forces that its shape distorted in the annular passage that surrounded it and what resulted were wear locations on the surrounding wall that defeated the seals that surrounded annular piston 26 or in extreme cases could distort the piston shape to a sufficient extent to cause it to seize in its bore and become immovable to counteract this effect noticed when the valve assembly depicted is in very deep applications that involve very high hydrostatic pressures on an annular piston 26 the design was changed to use rod pistons 224 which is in pieces and is exposed to connections 68 and 64 to which a control line not shown is connected preferably the rod pistons are arrayed symmetrically about the central.