Tip after stay option?

Hi again!

Coming over from Rover.  One feature I really like on Rover is that clients get to select their tip AFTER services are provided. I can’t see anyone wanting to necessarily give a tip beforehand. 

I see on scritches (using myself as a test client) that the client is asked to tip before if the business wants the invoice paid before.

Is there any way to make a feature where the payment is obtained and “paid” beforehand (I don’t wait until after because I don’t want to be chasing people for money) but they can add a tip after? 

If this is already a feature I apologize!