Thanks for bringing this my attention, @j0yfulone.

Allow me to step in and help share some information about the Bill with parent option. 

Ideally, this should work if you need to fill the billing address with the main customer's name and address. I've already checked if we have a reported case but we don't have any at this time.

I'd suggest reaching out to our Online Chat support so they can access your account and check this thoroughly. They'll be able to dig deeper and open an investigation if this can't be resolved with basic troubleshooting.

Just in case you need some helpful references in the future, you can always visit our site: Help articles for QuickBooks Online.

Please keep me posted if you have additional questions about setting up sub-customers. I'm always here to help.