Fixed cost projects: how to send partial invoices, how to track time for reports only
We often have fixed-price projects that span several month's time. They are split into 3 or 4 payments. So we need to be able to send invoices for a partial amount of the project cost, and describe it on the invoice accordingly ("down-payment", "2nd of 3 payments", etc.)
We sometimes need to attach expenses to the project and invoice for them.
Lastly, we also need to track time against these projects for our internal information only (never appears on an invoice).
What is the best workflow for these types of projects?