@MirjaK There in no separate approval flow for customer credit or correction invoice. However, this can be controlled using permissions.

Hope this helps.

Shehan Almeida. 

@MirjaK our business has struggled similarly in that we require customer credit invoice approvals over a certain dollar amount. We are also on APP10. Have you discovered an effective workaround?

I have created an Idea on the community to introduce this as a feature. Please vote on it if you would like to see this feature introduced!