The distributed control in elastic optical networks proposed in our previous work can reduce call blocking probability and connection establishment time by booking a reservation path and a tentative (second candidate) reservation path at a time. However, there is a possibility of failure in establishing both the reservation path and the tentative reservation path because reservation paths are decided independently. Therefore, in this paper, we propose an advanced optical frequency spectrum allocation method which allocates different optical frequencies to the reservation path and the tentative reservation path as much as possible and allocates the spectrum considering link utilization. Through, simulations, we show that proposed method can reduce the failure rate of the tentative reservation path in NSF topology compared with the previous method.