Half down; half on delivery - How do you invoice that?

I know of a business that charges $100 for a repair.

They charge $50 on acceptance of the job, then $50 on delivery.

One could issue two invoices, tying them together with a job for the customer. Post the first invoice immediately and process the payment. The second invoice remains unposted until the repair is complete. Then post that one and eventually pay it.

Is this the best — or only — way to do this, or is there another way?

Seems like a lot of extra steps.