6. Paragraphs 1 to 5 shall not apply to any parcel delivery service provider which had over the previous calendar year on average fewer than 50 persons working for it and involved in the provision of parcel delivery services in the Member State in which that provider is established, unless that provider is established in more than one Member State. A national regulatory authority may include in the threshold of 50 persons the persons working for the parcel delivery service provider's subcontractors.