Bleached blond hair does not happen over night for some. This was the 3rd session. Leo has natural black hair. It takes patience.
I recommend protein treatments at home before your next root touch up. Don’t wait too long before your retouches or else you will get a cool line of demarcation at the root area. I say no more than 3 or 4, weeks on really dark hair. If your hair is naturally light blond then you can go 5 to 6, weeks in between touch ups.