You can type into billing address any address you like. So yeah, you can issue multiple invoices to the same customer with different billing addresses.
Not sure what it means. Are you saying the customer name should be shown on invoice at all and only what’s entered in Billing address field should be shown?
I think they are saying that with that solution the Customer name stays as the Parent business name and doesn’t allow for the subsidiary business name to be used in association with changed billing address.
Why not put the subsidiary name as the first line of the billing address?
Depending on the volume, perhaps you could just change the Customer name/employee/address for each delivery, then change to Parent company for Statements etc.
Alternatively, set up all the locations as individual Customers then at month end - edit each invoice and re-point the Invoice to the Parent company Customer account.
You may also have to face the fact that some customers’ requirements for invoice submission are so strict that you have to prepare a custom invoice for them, or submit online on their system, or submit on their template, etc. Invoicing governments is often like that.
In such a case, it is probably not be worth the effort to force Manager to produce what the customer demands. Create a standard Manager sales invoice and transcribe the information to a mock invoice in the form the customer wishes to see it (in Word or Excel, for example). You get all the benefits of tracking things through your accounting system and the customer gets what they want. Plus, you get credit for following their instructions.