Nitrate output is a direct function of ammonia input. If there's already enough nitrifiers in say live rock to handle all the ammonia input, more nitrifiers beyond that will not somehow suddenly be able to yield more nitrates. At least where nitrification is concerned.They may eventually harbor denitrifying bacteria but they could also be loaded with nitrifying bacteria contributing to the higher nitrates. You have plenty of live rock so other surface areas for bacteria seem unnecessary.