In this paper, we propose a method to support handover between heterogeneous access technologies to multiple interface mobile node in the PMIPv6 (Proxy Mobile IPv6) domain. PMIPv6 enables network-based mobility for a regular IPv6 mobile IPv6 with no mobility management protocol. But, there have been some issues identified with supporting a host with multiple interfaces attaching to the PMIPv6 domain. This paper analyzes the reduction of handover signaling cost in the proposed MAG address translation method. It compares the handover signaling cost in required resource with PMIPv6 assisted by IEEE 802.21(MIH), fast handover mechanism for multiple interfaces MIPv6 and with the proposed method (i.e. PMIPv6-MAT) to show how much handover signaling cost reduction can be achieved.