If you are trying to stretch out your quick service credit, this is something that is definitely possible. My family, for example, is two adults and two children ages 3 and 9. When we went last time, we had quick service, but we also wanted to use these credits for breakfast, lunch, and dinner for every day in the park. On your account, it will show total quick service credits, not how many credits each person has. So for breakfast, we would get 2 or 3 quick service meals and share everything. We would do the same at lunch as well. Other than Be Our Guest, we never ordered anything off of the kid's menu. We always got 2-3 adult meals and just shared everything.
I hope this answers your question for you!