My opinion is this:
The critters that are in your rock that "eat" ammonia, obviously are well fed since there is so much of it. So, if you reduce the levels by doing a water change, you keep the ammonia level in a safe range, but you don't eliminate their food source. Drop the ammonia level to the middle of the acceptable range, and safe well fed critters will multiply fast!
Obviously if you take too much ammonia out of the water, the critters will be hungry for a while, but think about why you are worried. There is die-off in the rock that is CREATING ammonia. The ammonia levels will rise again. If you overdo it and do to large of a water change, your critters will be hungry for a short time, but the ammonia level will come back up and they will fing food. Nature made them tough little buggers, they won't die that easy.
I agree with reefrunner... it will speed up the process, not slow it down.