OK- I am in chat and also poking around the forum. Will look out for numbers. But it is really odd that in 24 hours both are at .25. Pretty much the entire time through a fishless cycle nitrite will always read higher than ammonia. The only time this will not be true is when there are some amount of live plants present which they are not here.
This still brings me to thinking your tank is cycled and you may regularly experience such low level readings when there is really no ammonia or nitrite present. This is where the "process" comes in. We know the specific strains of bacteria one will get depends on the amount of ammonia involved. This passes through to which nitrite oxidizers colonize as well. Dosing 3 ppm of ammonia should always produce the desired strains. Only dosing too much might change this. And you have been spot on re maximum ammonia for a while now.
We also know that the bacteria reproduce in response to excess ammonia or nitrite. This shows up in how fast the numbers of each change and the levels they reach after each ammonia addition. You numbers have gone down to practically 0 after 24 hours. And then they appear to have stalled. But the process does not support this sort of result. It tells us 0/0 is the goal. There is no way possible for .25 ppm reading to persist over time. If I offered you $1,000 to make this happen in a tank, my money would be safer than if it were in a vault. To come close you would need to buy many $1,000 worth of lab grade equipment.
So that leaves only one possibility. You are likely getting some false readings for some reason. The less ammonia or nitrite you might show at this stage, the faster it should vanish. Consider that about 2.75 ppm of ammonia was gone in 24 hours. That works out to .113 ppm/hour. And it also means that during those 24 hours there was enough excess ammonia present to get the bacteria to reproduce. So the processing capacity was increasing to some extent during that 24 hours.
Yesterday morning you reported 0 ammonia and .25 ppm for nitrite after the prior dosing. You dosed again and after 24 hours you say it is .25/.25. That would suggest you are going backwards on ammonia and have frozen on nitrite. Sorry, this is simply not possible as far as I am concerned.
So we come back to you must be cycled and ready for fish. I would still suggest that you monitor ammonia at least daily for the first week after you add fish. Any reading above .25 ppm and I would also then test for nitrite. I do not expect either to show up, but if either one does I am happy to help. One warning, full stocking does not mean adding as many fish as fit as long as you do not need a mallet and some oil to fit them all in
However, down the road if you will be adding a few more fish or have to replace a few, I would suggest you consider using a Q tank.
Also, when buying fish always spend time to checking things out first. Look around all the tanks in a store. Look to see if there are dead fish. All shops lose fish, but the good stores lose the fewest and are pretty diligent about removing dead fish when they do get them. Look to see if the fish look decently fed, buying wasted fish is rarely a good idea. If you are not sure of the information a store is giving you, come back here and post any questions. Remember, the hardest skill for most of us to master in this hobby is patience