In the example you provided you only did New Customers, I just attempted to apply those steps to all customers but my totals do not come out? I had assumed it had to do with duplicated data but maybe I misunderstood your example. Are you able to provide a file with the steps applied to Returning and Infrequent as well?
I want to use the same logic the previous poster used. We use "Reservation Number" in place of Mail #. I tried to follow the sample that you provided but you only provided the steps for "New". Can you explain how you apply the logic to Infrequent and Returning?