Skin Tone Development

I use the Skin Tone function to adjust colours in my interior photography so that walls and furniture has a more even colour. Sometimes I find that even if I select the full spectrum of colours this tool seems not to affect some of the colours I need to adjust. I understand this was developed as a skin tone function but it would be great to have a setting that would allow it to select the whole colour spectrum and become a more powerful colour and tone variance control.