Timesheet-only Sales Invoice

I’m trying to create a Sales Invoice that only has billable hours from Timesheets. When I try to save, though, it points out that ‘Item’ is a required field. You can’t change this requirement for a standard field. Is there some other way to go about this or must a dummy Item be populated?

I guess the general concept of invoicing against timesheets isn’t clicking with me. I’m able to fetch timesheet data and import it into the invoice. The billing amounts are carried over but do not appear as part of the invoice total.

I can assist if we can connect on shakeel.viam@gmail.com