Nowadays, most of the smartphones or mobile devices are already equipped with multiple interfaces. In general, the utility of multiple interfaces concurrently will escalate the device's performance of speed communication. In spite of that, an issue called performance anomaly when a new station (STA) with multiple interfaces aggregation and low transmission rate desires to connect with an access point (AP) exists. We can assume that a new STA connects to an AP which already has several associated STAs. Before turning an additional interface on for that new STA, we are obliged to consider the effect of this activity to the whole network performance. To optimize the utilization of aggregated multiple interfaces and diminish the performance anomaly (i.e throughput degradation for all STAs) all at once, a novel mechanism to predict gain (or throughput, equally) of each STA in the network based on its transmission rate is proposed. The current number of STAs, predicted transmission rate of dual interfaces from a new STA and each STA's time duration to send the packets are examined to determine the expected gain. After the investigation based on MATLAB simulation, we can optimize the utilization of a new STA's additional interface to achieve better average throughput in the network up to 10% and additional interface activation up to 92.2% of the simulation time while avoiding the gain anomaly of the whole network concurrently.