In Teachworks, invoices display each lesson as a single unit by default. However, you can customize units used for lessons to display in "Hours" by following the steps below:
Click on "Account & Settings" and then click on "Account Settings".
Scroll down to the "Invoice Settings" section.
Set the "Invoice Lesson Units" setting to "Hours".
Submit the form to save your changes.
NOTE: The "Create Invoice" form will still display each lesson as a unit after the change. However, your invoices will display the "Quantity" column in "Hours" when you view them after they've been created.