Nurse Practitioners as the Rendering Provider for Surgical CPTs

Does the 85% of the Physician's Fee schedule for a nurse practitioner's professional services only apply to the Evaulation and Management CPT® codes? Scenario: The NP sutured a wound in the ED and shared the E/M service with the physician. Shouldn't the suture CPT® code list the NP's NPI as the rendering provider and the physician as the E/M rendering provider? Will there be a 15% reduction in the suture repair reimbursement if the NP was billed as the provider? I am under the impression that the 15% reduction is liminted to the E/M codes.