If I previously passed the Coach Knowledge Assessment (CKA) for a prior Credential, why do I have to take the new ICF Credentialing Exam when applying for a higher level Credential?

Yes.  in alignment with global standards for certification bodies and to ensure consistency, fairness and equity in the Credentialing process, it is important that each candidate applying for a PCC or MCC Credential complete the same requirements. This allows all candidates to be held to the same standards and requirements as part of the credentialing process.