Invoices cannot contain more than one service plan. Currently, if a customer is signing up for more than one service plan, that means each will be on it's own invoice. When they go to pay - there is no way for them to check all of the invoices and sign/pay them all at once. They can only sign and pay for each individually - not a great customer experience.

Use case: We have an HVAC business and offer service plans. Many homes/businesses have more than one system, and each needs its own service plan. (Primary/first system, plus a plan for each additional system).