So once you have gotten the ammonia and nitrite to zero you continue adding three drops of ammonia per gallon? Even after the fish are in the tank?
No, as long as you are adding most of your fish at once, you can stop dosing with ammonia. The ammonia will then come from the food as protein---> nitrogen ---> ammonia.
If per chance one were adding only a couple small fish now and then planned to add a bunch more or several very large ones only a month later, it might be worthwhile to keep the ammonia up until the big additions were made. If not, the BB populations developed originally might dwindle significantly.
Most people would not do that, so it's more or less not a big deal.
The point to consider is that the BB population can and will increase to accommodate the tank but not instantly if the bioload is suddenly boosted 10 or 20 fold. Adding a lot of new bioload should lead one to patiently increase the feeding to allow BB growth to catch up. It will be soon but not instantaneous. A week would be enough time to ramp up for a 20 fold increase.