title: Product showing up in Amazon MWS API but not Product Advertising API
body: <p>I'm building an integration for my warehouse and using Amazon's API's to get product information from UPC.  I've ran into a number of times where a result comes back accurately from the GetMatchingProduct on MWS API but not from the Product Advertising API.  Even Vice Versa has occurred.</p>
  
  <p>Does anyone have any idea as to why this might be?  Is there a reason I should just use one or the other?  Thanks!</p>
  
  <p>Example: UPC - 363824072463
  MWS brings back ASIN - B0057UUHGU which is the relevant one that also comes back when you just search Amazon.  However the Product Advertising API does not return this in its list of results at all.</p>