We've had a ton of requests to show information (such as amount due, date paid, etc) about the client's last invoice on the current invoice. This will be available in Studiometry 9.0 using the following mechanic:
1. Add a new variable to your template
2. Select "Custom Variable" for the variable type
3. In the custom variable box, add either "CPI-" or "PPI-" and then type the regular invoice-related variable into the box. For example "CPI-InvoiceID" will show the Client's Previous Invoice (CPI) Invoice ID. PPI does the same thing, but for the Project's previous invoice.
The "previous" invoice is determined by sorting the invoices by date issued, and nearly all invoice-realted variables are compatible with this mechanic.