I am having the same issue. I want to use the modern template and customization settings, but I only see an option to add the aging schedule to the bottom of a statement, not an invoice. It works if you use an old form template, but since those are not supported anymore I would like to use the new format to avoid having to go back and redo things in the future when we are eventually forced to use the new format no matter what. How can I have past due invoices and balances show on invoices generated with the modern default template? I don't want to send statements.