Calculate days between 2 events

Here's what I came up with.  There's a few steps, but not to painful.  

Step 1:

• Get the data into Power Query.
• Figure out a way to remove exact duplicates.  Meaning same Park, Activity, and Completed Date/Time
• Create a copy of the Completed column, and change to data type to Whole Number

Step 2:

• Load that into the data model
• Add an "Index" column so we know what the previous date was:

  Index = 
  VAR CurrentPark= 'Calculate Dates Between'[Park]
  Var CurrentAct= 'Calculate Dates Between'[Activity]
  VAR CurrentCompleted= 'Calculate Dates Between'[Completed]
  RETURN
  
  CALCULATE(
      COUNTROWS(
          FILTER( ALL ( 'Calculate Dates Between' ) ,
          CurrentPark = 'Calculate Dates Between'[Park]
              && CurrentAct = 'Calculate Dates Between'[Activity]
              && CurrentCompleted >= 'Calculate Dates Between'[Completed]
          )
      )
  )

  
• Now we can write a measure since we have the data we need in the correct format:

  Days Since Last Cut = 
  IF ( 
  	NOT ( HASONEVALUE('Calculate Dates Between'[Index])),
  	BLANK(), /* this will put blank if there is more than 1 index (i.e. subtotals/totals*/
  		IF( MAX('Calculate Dates Between'[Index]) <>1, /*do not want a value on the 1st date, so will put "First cut"*/
  			MAX( 'Calculate Dates Between'[Completed - Whole Number])-  /*Current Whole Date in the current filter context*/
  				CALCULATE( 
  					MAX( 'Calculate Dates Between'[Completed - Whole Number]), 
          				FILTER(
              			ALL( 'Calculate Dates Between'),
  						'Calculate Dates Between'[Index] = MAX('Calculate Dates Between'[Index])-1
  						), /*want to filter that whole number column we created by taking the current index and going back one */
  					VALUES('Calculate Dates Between'[Park]) /*need to keep the filter on Park in play*/
  				),
  		"First Cut" /*Value for 1st date, could be anything
  		)

  Seems like a lot (and it is!) but when broken down it's not so bad.....

Here's the final output:

Hopefully that makes sense, but fire away any questions