When editing a custom invoice template using a custom layout. How do I change the columns and/or the titles of those columns for unbilled time that has been added to the invoice. Below is a screen shot of what I would like to change.  The use case: We often bill projects as single line items and it is confusing for the client to see "Project Hours" listed as "1". Ideally this should be "Quantity" or not be on on the invoice at all

It's worth noting that I am able to edit the item table for manually added items not related to unbilled projects.