Q: Problem with Ask to Buy and Family Sharing

I'm having an issue with the Ask to Buy and Family Sharing features.  They work great to share apps and keep my kids in check with what they load onto their iPads.  Problem comes from something that is already in their purchased list, or any of the other family members purchased list.  When they install an app that previously purchased, they do not have to "ask" again.  There are apps that we allowed them to play before, but have lost the privilege of doing it now.  When I uninstall the app, they can reinstall it without asking.  Is there a way around this without doing a restriction for installing app in the restriction settings?

Thanks

Kevin