One question I did have on the monk skin tone scale. They note that tone (normally a color measurement) is actually subjective (not objective) and so participan

One question I did have on the monk skin tone scale. They note that tone (normally a color measurement) is actually subjective (not objective) and so participants in studies should be asked to self identify their own skin tone and not let the computer classify images based on the scale. To the degree self identification is materially different than a technical measure of skin tone, how does that work in a model (ie, someone who is white self identifying as having a black skin tone). Secondarily, are these tones intended to map in any way to any traditional measures of ethnicity / race / national origin?