Here is a start of response...
Least square flatness :
ASSIGN/FLAT1=MAX(DOT(PL1.XYZ-PL1.HIT[1..PL1.NUMHITS].XYZ,PL1.IJK))-MIN(DOT(PL1.XYZ-PL1.HIT[1..PL1.NUMHITS.XYZ],PL1.IJK))
It gives the result of Feature location - form for PL1. It's not the Chebychev flatness.
Least square roundness :
ASSIGN/RAD=CROSS(CROSS(CIR1.HIT[1..CIR1.NUMHITS].XYZ,PL1.IJK),PL1.IJK)*SQRT(DOT(CIR1.HIT[1..CIR1.NUMHITS].XYZ-CIR1.XYZ,CIR1.HIT[1..CIR1.NUMHITS].XYZ-CIR1.XYZ))
"RAD" projects the hits of CIR1 on PL1, for manual hits for example.
ASSIGN/ROUND1=MAX(SQRT(DOT(RAD,RAD)))-MIN(SQRT(DOT(RAD,RAD)))
Round calclates max and min radii.
