Right now you have a Xero integration which means I can create an invoice in Pipedrive. This does not solve the flow of how any business works with an accounting software. 

  1. Sales process which means we create a quote/proposal
  2. Win deal and now need to create invoice
  3. Products in Deal now should have option to auto create invoice in .... (Our case, Xero)
  4. Draft invoice raised in Xero (Products, Organisation details, possibly/hopefully custom field)

Your current process is manual and I may as well go straight to Xero. Other than the obvious benefits, this also means that your Pipedrive becomes central point for all products and ultimately what a CRM should do.