Invoice Options

While creating a listing on the backend it gives an option to create an invoice, though it only allows for one amount to be entered.  I realize you can edit the invoice later, though it would make the work flow easier if I could create an itemized invoice while creating a listing.

Something where I could select from my services or even input multiple items manually.

Also, I saw this mentioned before, though I would also like to add it would be great to be able to create an invoice without having to create a listing.