Currently, if you want the invoice email to be the only one receiving that information, you have to update the email from the main client profile, as the check mark only sets the additional contact information to be Cc'ed.

That seems unreasonable, especially since we have automated emails that send invoices, so we are unable to delete the unwanted email address. We should have the choice on the client page or the job to choose which email address and billing address invoices go to. We should be able to edit this information as they change.