Sorry to keep you hanging. I’ve gone through a few ways to process this and wound up having something over-complicated most of the time, especially to maintain (some with 20+ automation commands, actions, and rules).
So, here’s something simple I’ve come up with:
THis is just adding a tip, then paying it (if needed):
This is when a ticket is paid in-fill via cash and there is tip left so it needs to be added (the functionality is the same with credit card, just using a different payment account):
Let me know if this would work for you. If so, I’ll post the configuration procedure.