We address the problem of estimating direction-of-arrivals (DOAs) for multiple acoustic sources in a reverberant environment using a spherical microphone array. It is well-known that multi-source DOA estimation is challenging in the presence of room reverberation, environmental noise and overlapping sources. In this work, we introduce multiple schemes to improve the robustness of estimation consistency (EC) approach in reverberant and noisy conditions through redefined and modified parametric weights. Simulation results show that our proposed methods achieve superior performance compared to the existing EC approach, especially when the sources are spatially close in a reverberant environment.