ammonia chips in a matured filter are useless, as the BB in the filter media is capable of removing any ammonia from the tank. if you have any ammonia reading whatsoever, it means your filter is not fully matured, and needs to finish cycling.
if your filter is not fully matured, and you add ammonia chips, the ammonia chips are removing the ammonia before the bacteria can use it as a food source. this will stop your filter from ever fully maturing and render it incapable of handling the ammonia levels on its own.
the bacteria colonies in your filter grow only as large as their available food source (ammonia) dictates. if your ammonia chips are removing the food before the bacteria can feed on it, the colonies do not grow large enough to handle the actual amount of waste being produced my your stock.
also, ammonia chips (as well as carbon, and other chemical media) are only meantto be temporary. activated carbon is only active for 5-7 days, and i believe ammonia chips are active for only a month. after this time, not only is the media no longer being used, and taking up space in your filter where functional media could be, but it also runs thr eisk of leaching nitrates and other bad things back into your aquarium.