Hello! Isn't it possible to update a billing schedule once the SO is saved? Client created a SO with a custom billing schedule and saved it. They didn't create an invoice yet. She then had to update the custom billing schedule with different amounts, but NetSuite won't take those changes.

Have you tried editing the SO by selecting a different billing schedule then select again the actual billing schedule to be used? If it didn't work, try saving it with a different billing schedule then edit and save again but with the correct billing schedule. From what I remember, NetSuite doesn't really automatically update the billing schedules used on transactions.

Thank you @Luis! For custom billing schedules for a SO with multiple lines, should I use % instead of a fixed $ amount?

Yup. That's right! It's more flexible.