NPK value disclosures :

The NPK value is the value of plant usable materials in % to the mass .
This is the weight for solid fertilizers as well as liquid fertilizers.
(1 liter of liquid fertilizer weighs just under 1.2 kg )

For solid manure , an entire NPK value is already quite violently by 60 and almost the maximum of what is possible .
For liquid fertilizers , it is difficult to surpass a total value of NPK 18 .
(NPK 6-4-5 NPK = Total: 15)

N, P and K are not available in pure form – they are always included only in proportions in the starting materials .

Urea , for example, contains about 46% N ( almost half ). In order to achieve an N value of about 5 % to 1000 liters of water are required ca 125 kg.
However, other starting materials also contain only 20% of N , P or K.

For liquid fertilizers , the solubility of the components is still too limited and the solution also be saturated quickly.

Furthermore, additives such as trace elements need to be added or etc. .

Conclusion:
Liquid fertilizer with an NPK of 20-10-15 have a big error on the label.
That’s just not possible.

with flowering regards

Eddy