When you do a search through the affiliate sales stats, you are only shown stats on sales made directly through affiliates, not the vendor. It also does not show any sales that have resulted in a refund.
This is usually why the stats do not seem to be exactly what you would expect them to be. To obtain more accurate stats go to the Sellers tab in your JVZoo account. Under that tab click on Reports then select Sales. Here you will see the detailed stats on your own product(s).