Here is my approach.
First, create "Date list" which consists of both Start and End date.
Otherwise, Start and Date does not necessarily match and calculation becomes incorrect.
Create calculated fields.
if [Pivot field names]="Start Date" then [Name] END
if [Pivot field names]="End Date" then [Name] END
[Count Start Date]
[Count End Date]
[Starrt - End]
running_sum([Count Start Date])-running_sum([Count End Date])
Start_End_Caluculation_9.3.twbx 25.3 KB