Client Centered Therapy [CCT] and Person Centered Approach [PCA] are different. Client Centered Therapy came first. It was the rootstock of Person Centered Approach. Carl Rogers described it in 1957 as necessary and sufficient for therapeutic change.
Carl, himself, moved beyond therapy. He quit doing it. He focused on world peace, education, personal power, personal partnerships and other applications. He stopped doing therapy himself. He would continue to train therapists. He changed from Client Centered Therapy to Person Centered Approach. I notice that Brian Thorne in your journal noted Carl’s shift in his later years.