Increasing the number of channels beyond the current design would require a much larger custom chip, which is probably not practical at the start of the MMA project. Possibly one could replace the correlator chips in an interim MMA correlator after a few years with chips that have many more lags, potentially yielding 4 to 16 times more channels. The difficulty with allowing such an expansion path is to design the system downstream of the correlator chips to handle the future expansion in data rate and quantity. One way to do this would be to do little or no processing on the lag data in the correlator chassis itself, doing all post-lag computation in completely separate racks that could grow as advances in computer technology occurred.
Such an expansion would also require that the power consumption per lag be reduced in proportion to the increase in the number of lags. If such a new chip required a different operating voltage, there could be further difficulties.