We have investigated the use of complex tool electrodes (templates) in electrochemical machining with ultrashort voltage pulses using a three-dimensional computational model. Through a systematic study of profile evolution varying pulse durations and separations between features, we have quantified the degree to which the performance of these templates is decreased relative to that of a simple tool electrode. We have found both the discrepancies and the separation at which the maxima occur are reduced with decreasing pulse duration. We explain these discrepancies through examining for the first time the effects of intratool electrode interactions on the overpotential and dissolution current at the substrate electrode. These studies have revealed that overpotential is largely additive among the individual components of a tool electrode above a critical separation between components, while the exponential nature of the dissolution current with respect to overpotential leads to increased dissolution when using a complex tool electrode.