We analyze the economic effects of mobile termination rate asymmetry by simulation model. The asymmetry allows the mobile operator to get access profits at the expense of the incumbent and induces negative effects such as the entry of inefficient operator and allocative efficiency as well as productive efficiency. We use simulation model to investigate the effect on social welfare of asymmetric regulation. If the brand loyalty is high, social welfare increase as the termination charge of entrant increases. The extension of the basic model shows that the degree of social welfare increase becomes higher as the brand loyalty increases when the cost of entrant is smaller than that of incumbent. But, the degree of social welfare decrease becomes lower as the substitution effects increase.