This app hasn’t worked right since the latest update, every tone direction I choose is way off, like I choose chocolate on a level 5 base and I’m shown ashy shades with a -21. I also don’t see a use for this app, unless someone has no knowledge about hair coloring with schwartzgopf or the color wheel and even then, there’s not a whole lot you can do with formulas using the color wheel, like no option to cancel out unwanted undertones.