I had opportunity to keep both variety as very young fish, less than 1 inch at the same time in my tank and watch them developed. As as young fish, less than 1 inch, the Yellow chest and Blue chest looks the same. They base color of the fish is yellow, as they developed, the white/Blue-black bars developed. In the Yellow chest, these line stop developed earlier result in a more yellow fish. In the Indo Pacific region, the darker coloration continue to developed longer result in wider white/blue bars and more darker coloration on the face and chest.
One can say that the color development of the Indian Ocean and Red Sea variety were arrested while the coloration developement of the Indo Pacific variety continue longer result in more white, and blue-black. Wider white bands with thicker blue-black borders around it.