Minimum Zone affecting Axial Runout

[[Se...]]

Hi all,

Looking for some guidance, got a fixture I am measuring the axial runout to Datum plane A.
Datum plane A on the underside is made up of 9 pads, 6 of which are equally spaced around the outer diameter, remaining 3 equally spaced in the middle. The upper part is made of 5 equally spaced pads.
The runout consistently fails however I suspect this down to the Minimum Zone calculation on the Datum face, the max and min of this face are 2 pads inline with one another and immediately adjacent, outer pad the biggest (outer tangential) the inner pad smallest (inner tangential?), is the Minimum Zone fitting a plane at a steep angle due to there closeness?
If I swopped the smallest pad and moved it further around the fixture, away from the biggest pad, will I reduce the Minimum Zone?
Or if I pack the smallest pad with a shim, so the min reading moves elsewhere?
Apologies if this is difficult to follow, I know what I want to say but not very good with my words!
TIA