j) a building site or construction, installation or assembly project or supervisory activities in connection therewith, where such site, project or supervisory activity continues for a period of more than six months, or where such project or supervisory activity, being incidental to the sale of machinery or equipment, continues for a period not exceeding six months and the charges payable for the project or supervisory activity exceed 10 per cent of the sale price of the machinery and equipment;
4. A person acting in a Contracting State for or on behalf of an enterprise of the other Contracting State—other than an agent of an independent status to whom paragraph (5) of this Article applies—shall be deemed to be a permanent establishment of that enterprise in the first-mentioned State if: