Adding New Invoice Overview Option To System

I was wondering if anyone knows of the location of the settings for “invoice overview?”

I have located the area in the form to add options to the drop down on the admin side of the site, but I cannot find where the initial options are defined for the program. I would like to add an “all time” option to the overview period that lets the user see the entirety of outstanding balance since we began tracking invoices with the system.

Any help or guidance would be much appreciated.

Thank you,