(4)Where,––(a)the Central Government has entered into an agreement with the Government of any country or specified territory, as the case may be, under sub-section (1); or(b)a specified association in India has entered into an agreement with a specified association of any specified territory under sub-section (2) and such agreement has been notified under that sub-section,for granting relief of tax, or avoidance of double taxation, then, in relation to the assessee to whom such agreement applies, the provisions of this Act shall apply to the extent they are more beneficial to that assessee.