How can we improve WHMCS?

We have a few customers that own several companies, also there are many, agencies, freelancers and so on that need have the invoices sorted by company depending of service.

At the moment we can assign the billing contact server wide. would be a big advantage to be able to be more granular, per-service billing contact.
that would help customers organize things in a better way and to use the invoice would be created with right details at once.