Need to find elapsed time between to dates times and then cost according to time elapsed

Hi
I am trying to run a spread sheet to log alarm call outs (start and end time). Mostly overnight and so can span midnight.
Once I've captured the elapsed time I need to calculate the charge for the first hour and the charge for the subsequent hour ( or part hour) to give a charge for attending the call out.

I have used all suggested ways to calculate the elapsed time but without consistency.

I have tried to attach a sample sheet but don't seem to be able to add one

Are you sure your Start Time is 10:00 PM and End Time is 11:00 AM in the same day???

Your start time on the second row is after the end time. Are you sure you have the correct dates of 04/30/2018?