For RF operation, each contact behaves in a more complex manner. It has to be modeled as an inductance with some capacitance and resistance. The DC resistance is as pointed out above is around 4 ohms per contact. That's why having multiple contacts reduces resistance and improves current flow, and reduces capacitance as well, which may become a high reactance at a certain frequency. Xc=1/(wC)
Check your RF models for a detailed discussion as it relates to the technology that you are using and follow any guidelines there.