In our previous work, we proposed a distributed server architecture to deliver multi-party immersive voice communication service to mobile clients (e.g. Sony PSP) accessing a distributed virtual environment (DVE). We refer to such immersive voice communication service as mobile immersive communication environment (MICE). We also proposed solutions to assign server to create the auditory scene for each avatar. In this work, we ascertain the necessary update period of server reassignment in order to cope with avatar mobility in the virtual world. In our simulations, we measure the percentage differences in delay deviation and bandwidth cost between the case of no server reassignment update since t=l second (the initial time instant) and the case of ideal server reassignment at every second. Our results show that the impact of avatar mobility leads to increases in both delay deviation and bandwidth cost as the time elapse further from t=l second. Such increase in delay deviation and bandwidth cost is more significant at the low avatar densities than at the higher avatar densities. The optimal server assignment algorithm is found to be too computationally intensive to be executed within the required update periods. A much faster greedy heuristic has been devised to perform server assignment within the required update periods.