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I regularly prepare quotes for new projects which include multiple items. It is useful to transfer this to an invoice but I regularly work on projects that can last up to a year or more and for which I issue invoices monthly - some times this will include 100% of a particular item or at other times a lower percentage. At present there is no way of keeping track of this, so I have to maintain a separate spread sheet and then re-do the convert to invoice and amend manually each time I issue an invoice. It would be so helpful to have a facility (as you do in for payments) to monitor how much of each item against a quote has been invoiced.