Amazon MWS - Submit Feed - Add Product

Question

I'm trying to add a new product to my seller account, using SubmitFeed function (feed type being _POST_PRODUCT_DATA_). Everytime I try it, a different error comes up. Want to confirm if I understand the underlying concepts correct.

ISBN/UPC/EAN are standard global identifiers used to identity a commodity uniquely. ASIN are standard Amazon identifiers used to identify a commodity on Amazon uniquely. SKU is my personal unique identifier.

1. So, if I want to sell a product that is existent on Amazon, I can specify ASIN/UPC/EAN/ISBN. What is benefit of providing Description Data as it won't affect the description already showing on Product Listing Page on Amazon
2. I can add a new product (not existent on Amazon) by specifying my local SKU and omitting any ASIN/UPC/EAN/ISBN. Are there any specific rules for mandatory fields/data to be specified while adding product with specific categories/product-types?

Answer 1

Your understanding of the underlying concepts seems accurate.

1. There is no direct benefit to providing tons of details to an already existing product. Unless Amazon for some reason switches to "your" data from whoever else's. There are rumors of that happening, but I haven't had such a case myself.

2. For the most part, you cannot add a new product without specifying a ASIN/UPC/EAN/ISBN. There are exceptions to this, but they are few and far between. It is in Amazon's interest that identical products will be on the same page. If the description or other information on that page is wrong, contact Amazon. Apart from what the XSDs define as mandatory, there are category specific mandatory fields. The easiest way to find them is by creating a product manually in Seller Central.