Configurable List Widget: calculate the total hours worked

Unfortunately, it is not possible to calculate the total hours worked for the time fields in the configurable list widget.

You can consider using Form Calculation widget in order to calculate the difference between two times. 

Furthermore, We have date difference widget as you can find it at the following link: https://widgets.jotform.com/widget/dates_difference 

I have forwarded this request (calculate total hours worked in the configurable list widget) to our software development team in order to consider implementing this.

Thank you for your interest.