Activity Table Start - End date Configuration

Dear all,

In my analysis I have a Start and End date for each activity in my cases, in which activities happen concurrently. When calculating the throughput time of a case, the time between both the start dates of the activities is used, while I expect the start date of the first activity (using Sorting to ensure this goes right) and the end date of the last activity is used to calculate the throughput time. Does anyone know how I can fix this?

As you can see the activities start three days after each other, but the whole process takes 10 days actually.

As I was only able to post 3 pictures, here is the last one to give more context: