When Amy came to afrodita she had a slightly messy haircut. She wanted to clean it up and get something like a bob hairstyle, without losing too much of the length though.
So Yoshiko cut a bit of the ends and shaped her hairstyle up. Added bangs to complete her bob style.
She also wanted some more color to her hair, lighten it a bit up, without overdoing it. So Yoshiko created a lighter color via some subtle highlights.