Agree with most of what Diana said. I would do two additional steps:
1. Test the test kit
. Maybe buy a second one, different brand. Do you get about the same result ?
2. Test your fert... add enough to 5-10 L of RO/DI water to obtain 2-3ppm and test to see what the kit says. If you are sure about the fert and the kit says different than the kit is wrong.
Many times when I observe extreme values that I did not expect, I suspect the test kit /test method as well. Also be careful to look at the test result after exactly the amount of time the manufacturer says to.
/* Sidenote: 'most ' and not all just because of a personal view on nature. I do not consider the elemental proportions inside a plant to be a guideline for what should be outside the plant. One would not compare the concentration of Oxygen in the atmosphere or in food with that of the human body. Too simple point of view ? Maybe consider these as well.
1. Most elements are used in very complex molecules inside the plant while some elements are just stored away to be less toxic or as pure storage. So what is the plant might me more than needed, or not needed at all.
2. Different elements concentration/proportion will be found in different organells of the cell, each organell might have different environmental conditions. Even inside the chloroplast you will see very controlled different conditions. Nobody will say a equal concentration of O present as O3, O2 and CO2 is the same for the plant.
3. Proportions will change in different stages of the plants life.
4. Outside the plant elements become unavailable for plants (Fe and PO4), less availabe (NO3 vs NH3 ) outcompete with others for plant uptake, help others enter the plant (Fe and Mg).
As Diana correctly said, there is no need to hit this value. I understand the need to use these type of values as comparison of plant performance but they are not about plant requirements.
*/ End rant.