Adapting a λ-tunable wavelength division multiplexing (WDM) / time division multiplexing (TDM)-passive optical network (PON) that can control huge bandwidth is an attractive candidate for accommodating the explosive growth in mobile backhaul (MBH) network traffic cost effectively. The synchronization of base stations is an important issue for MBH. However, it is hard to employ conventional time and frequency synchronization techniques over λ-tunable WDM/TDM-PON. We proposed a timestamp-based time and frequency synchronization method over a λ-tunable WDM/TDM-PON. In this letter, we describe a numerical evaluation of the synchronization performance with practical oscillators. The achieved performances are sufficient to meet the requirement of MBH.