Joining in the thread to share more details, howardjennings.
You would usually need to use sub-customer if you want to break down or want more details with your reporting in QuickBooks. For example, use this feature if you want to track multiple departments under a single account with separate or combined billing.
You'll want to use the Bill this customer option if you don't want to have the balance added in the parent account. On the other hand, select the Bill with parent option if you want to have the balance added in the parent account.
When running financial and transaction reports, there's also an additional filter where you can drill down how much is your income for this department or sub customer. Feel free to check out these articles to get more details in case you want to get more information about customizing reports:
As always, feel free to reach out or add another reply below if you have follow-up questions.
