How does Pocket retrieve data from Shopify/Amazon and recognize sales?
When you connect your Shopify/Amazon accounts to Pocket, that integration enables Pocket to pull in the sales from those commerce platforms.
Pocket receives the Gross Sales, Discounts, and Returns. Thus you will see Gross Sales recorded into your Sales of Product Income - Shopify (or Amazon) account as well as Discounts and Returns recorded into your Discounts and Returns - Shopify (or Amazon) account.