This circuit has Acm = 1 - (R2*R4) / (R1*R3) & Ad = 1 + R1/R2
If for the worst case CMRR, Acm should be large, so the algebric term in Acm should be small.
then I thought it would be
For a normalizedAcm representation (values between 0 and 1) only your representation can be correct, s. the PDF below: View attachment Acm-Calculation.pdf