Count a sale for a customer only outside of 15 days from the first sale, and any subsequent sales

[ahabelow13]

My dashboard for customer sales has many "duplicates". For example:

Customer Bryan Smith has made 7 purchases in the past year total. For my specific dashboard, I want to filter out the cells that are not highlighted in green (rows 3, 7, and 😎 because they are within 15 days of a previous purchase. I have a Customer Key (CusKey) as a unique identifier for my customers.

The calculated column I created is:

dupeTest =
VAR MaxDateKey = 'Sales'[DateOfPurchase]
VAR MinDateKey = maxdatekey - 15
VAR Calc =
CALCULATE (
COUNTROWS ( 'Sales' ),
FILTER (
'Sales',
'Sales'[DateOfPurchase] >= MinDateKey
&& 'Sales'[DateOfPurchase] <= MaxDateKey
&& 'Sales'[CusKey] = CusKey
)
)
RETURN
IF ( calc > 1, 0, 1 )

And then to get my desired result, I filtered out all 0's in that column so those entries wouldn't be in my data.

The data I'm trying to filter out is still present. In this specific example with my formula, row 3 would be erased because it is within 15 days of row 1's date (this is what I want). Row 7 and 8 still remain although they are 15 days within row 6. My desired results after implementing that formula is as follows:

Help would be greatly appreciated!

[lbendlin]

IF ( calc > 0, 0, 1 )