I paid for fullhead coloring via treatwell, but when the stylist was done, she made me pay 30 euros extra. I tried to ask her why she was charging me more even though my hair was only shoulder-length. She reasoned out saying that my hair was still considered long and the price I paid for was only for outgrow/roots even though I obviously paid for a fullhead of color.
The color was good, and the stylists know how to adjust to your natural hair color. Eg: my hair has natural copper tones which they toned in order to get an ashy color.