I used to run my Auto Upholstery business that way. It incentivizes the workers to do more work and earn more pay but still keeps quality high. They do more, make more and so do I.
My guys got base plus. Base work plus whatever they finished beyond that in a day. If they got part way finished but did not complete, they got the work done as a credit on the next day’s base. If they stayed late and completed it, they got full payment for the overage on that day.
Sometimes I would leave the shop for the day and they were still going. I would reconcile the work done the next morning. Some of my guys would double their pay in busy weeks. If we were slow, they were always guaranteed to get base even if the work wasn’t there. I ate it, not them.