...and upon what information I provided tells you that? Poke yourself.
All the info tells that if you listen to it.
The fact that you have not fertilized.
The fact that you have living moss which indicates a healthy environment.
The fact that plants do require nutrients to grow.
Since you have not added nutrients and the plant is growing well my theory is that the moss itself and/or organisms it harbors are producing the nutrients the plant needs to grow. Further since if you measure the flow through you would likely report there are basically no dissolved nutrient salts then it is likely the nutrients are being supplied in a form other than NPK dissolved elements (amino acids, ect).
From what I've seen over the years and what people report when there are plants that people have growing extremely well without ever fertilizing them there is also a very well established "living" environment around the roots and foliage (as in Nature). I doubt the plant would have grown so well if it had been in pure LECA rather than living moss.
That is why some people have luck with using very little fertilizer and others don't.