Q: Can I disable "ask to buy" for free apps?

At first I was happy to get the ask to buy feature - I thought it would get rid of the stupid sign-in-sign-out process (my son uses an Apple ID with no payment option to install free apps and then I switch to my Apple ID whenever he needed a paid app).

But Ask to buy requires permission for every "purchase" - even free ones! I don't get it. I have age restrictions set up to manage appropriateness (is that a word?) but I want to protect my wallet .

We enabled family sharing, but disbaled it again after less that a day. The kid was getting angry having to ask permission for each free trial game install and I was getting tired of having to approve all the time.

If there is a way to disable the approval process for free apps I would love to hear about it!