I think a tank should be able to handle its own ammonia biologically. I also think an ammonia spike would be worse with a control product. Bactieria grows to suit its need, it will grow more if its needs are there. The more healthy bacteria you have, the easier to expand.
This example might help:
(numbers have no correlation to PPM
, just a example amount)
If you have 100 ammonia parts, 25 of them are getting cleared up by the control product and 75 of them are getting converted biologically. Then you have a 25% spike to 125 ammonia, still only 25 are getting cleared up by the control product. So now you have 100 that need to get converted biologically. It actually gives you a 33% spike on your bacteria which makes it harder for your bacteria to catch up.