in the multiple insert behavior, you are binding the product ID columns to the recordset rs_product.ProductID column.
the reason this wont work is because this recordset does not have any filtering, this means that the value in the recordset will always be the first record in the database, it will not use the value for the product that was just inserted.
On the product insert page, the product ID of the record that is created gets stored in a session variable named "WADA_Insert_products".
you should that session binding for the productID columns in the multiple insert behaviors.