In my opinion this clause does not change the 21 days presentation period. It simply means that if shipment takes place less than 21 days from expiry that docs must be presented before expiry..... which would be the case even if the clause was not there.
Rgds

Hi AAtiyeh, The answer to your first question is "no". The definition of Presenter in UCP anticipates that documents may be presented through a third party that is not a party to the credit, whether this be a bank or a non-bank entity. It's the documents that are important, not who present...