SME is Samsung Electronic Msia while AP stands for I think "approved or alternative product" - is a 3rd party import by other importers not through samsung Msia. So warranty is handle by the importers and not by the usual Samsung service centers
And if you wish to buy AP , buy from those with shops and are reputable. I would advise you not to buy from 3rd party resellers who is freelancing and does not have a shop. Simply if you need warranty claims - it will be a headache as the reseller will probably pass it back to A who will pass it down to B or even C than only back to the actual importer