Fishless cycles are performed for a few reasons:
1. To spare fish from a cruel death / torture during the cycle
2. A fishless cycle is quicker than a fish cycle. Some may debate this but mine have taken 21 or less days.
3. To allow you to fully stock your tank at once at the end of the cycle.
If you just finished a fishless cycle and you DONT add all of your fish at once, your bacterias will die off leaving only enough to support the fish that are in the tank. When you add more fish, you wil go through a mini cycle each time. This won't happen if you fully stock your fish now since the bacteria levels after a fishless cycle are much higher than you would have with a fully stocked tank. (if you added 2-3 PPM of ammonia each day during the final stages of cycle). Just make sure you do a major 50-75% water change to drop your Nitrate down and you should be able to fully stock. You MUST continue to add ammonia every day untill one day prior to adding fish or your bacteria will die off.