The network model of interstrand contact resistances (ICRs) is often used to describe the flow of interstrand coupling currents in Rutherford cables, and to predict the contribution of these currents to the ac losses of such cables. Recent evidence indicates that in cored Rutherford cables, the interstrand resistances are significantly lower in the cable edge region than they are in the flat area of the cable. To investigate these non-uniformities, the VI method was used to determine voltage profiles for cored cables of varying length. The results of the measurements have implications for both the measurement of ICRs via the VI method, and the calculation of ac losses.