By way of derogation from points 1 and 2, and where efficient management of fishing opportunities so requires, a Member State may allocate to vessels flying its flag the right to additional days absent from port where an equal amount of days absent from port is withdrawn from other vessels flying its flag that are subject to effort restriction in the same area and where the capacity, in terms of kW, of each of the donor vessels is equal to, or larger than, that of the receiving vessels. The number of receiving vessels may not exceed 15 % of the total number of vessels of the Member State concerned, as indicated in point 1.