[en] In this reply we respond to the comments of MochaIskyy et al on our paper ‘Issues in the understanding of negative ion extraction for fusion’ where we pointed out some errors in previously published papers reporting results of particle-in-cell Monte Carlo collisions of negative ion extraction. We stress again that (1) it is always better to solve properly a simplified problem than to present misleading simulation results albeit under conditions closer to the real problem and (2) good comparison of simulation to experimental results does not constitute validation of the simulation if accuracy of the simulation is doubtful unless thorough verification of the simulation has been carried out. (reply)