Can you please attached a workbook for us? We can help you faster by using your own 'sample' data.
Here comes the worksheet and sample data.
As you can see in the file "Tableau 1". I set up the "Unique Deal" calculating table base on SO Nbr and Restarting Every Customer ID. Now by counting all number 1 (Sheet 2), I can come up with number of Deal. I want to know how much $ Amount associating with 1 Deal.