We investigate the performance of our recently proposed novel subsystem modular OXC node that achieves graceful modular growth without any service disruption. Simulation experiments under a realistic traffic increase scenario verify that the node architecture offers almost the same performance as the conventional large scale OXC node, while greatly reducing the number of WSSs needed and allowing the use of small degree WSSs. It is shown that both the number of WSSs traversed and total end-to-end optical loss can be substantially reduced.