incorrect account for purchase approvals on my child's account

I have parental controls on my child's account for his iphone. I have require purchase approval set up.

But when he tries to purchase free of chargeable items from the app store it defaults to his email account for approval. I can't see to find where to change that... I even deleted his account from family sharing and added again to start new and it still has his email account for approval?

Any help is appreciated.