sorry but I really don’t get it
let’s say some employee every day from 2/01/2023 to 2/16/2023 check in at 8:00 AM and Check out at 4:00 PM , so he worked 128 hours
128 hours is not a difference between 2/01/2023 and 2/16/2023 (15 days), 128 hours are just 5 days an 8 hours (but I guess you meant 2/06/2023 as the end date ).
So your exact example tested:
Could you share your date/time pickers setup and the expression?