Hi,
Yes, fundamentally the numbers look fine. Here are some finer points that may either clarify things or confuse you further:
Remember that this is the "estimative" index so there is no way you'll enhance your accuracy by accounting for that 0.15 size factor. Just call the tank 3X as large and let the rounding of the fractions take care of you.
19 teaspoons of MgSO4 is a lot, I realize that, and that's used as a worst case scenario. If your water report reveals that your tap has plenty of Mg then there's no need to up the dosage from 6 to 19. Again, EI is an interactive procedure. It is not meant to be rigid. It's for the thinking aquarist and NOT for the Lost in Space Robot Automaton.
For example, you can easily change the MgSo4 dosage to 19 and see if there is an improvement in growth rates. If there is no discernible enhancement then that means your 6 teaspoons will suffice. When it comes to the micronutrients like Magnesium, Iron, Calcium and so forth, you have a tremendous leeway because the plants don't use very much of these elements, they just need to be present, but not necessarily at high levels.
On the other hand Carbon, Nitrogen, Phosphorous and Potassium (CO2 + NPK) are vital and are used in large quantities. All critical functions in a plant, such as food production and storage, photosynthesis, protein production, DNA/RNA synthesis, involve these four. If you have algae, it's because your have poor effective levels of some or all of these, so I don't trust any water report values for NPK. Unless the municipality tested your specific water line, the value could just as easily be 3.6ppm NO3. So with macronutrients, start your dosing as calculated for about 3 weeks or so and ensure that you do not suffer malnutrition. Then make up a new batch with say, a 10% lower KNO3 dosage and use up that batch. If you don't see evidence of Nitrogen starvation , such as BGA, then on the next batch lower the KNO3 by another 10% and use that up. Continue this iteration and you'll find that at some point your start to see a nibble of malnutrition, perhaps some BGA or some yellowing on mature leaves. this tell you that you have gone too low on Nitrogen reduction, so just return to the previous level.
So instead of chasing voodoo test kit readings, you allow the tank to tell you what the status is and you can take appropriate action. You never really need to know exactly what the tap NO3 value is. You only need to know that "tap + X dosage of KNO3 takes me where I want to go".
As Keymaker rightly points out, you may be able to drive the KNO3 dosage so low, due to tap water NO3 content, that you would then need to supplement K+ and that's when you may need to supplement K2SO4. Again, I personally have absolutely no fear of KNO3, so I never even think about what's in my tap or what's in my fish waste. I just carry on as if the tap NO3 content and NO3 due to fish waste were zero. This means I never suffer problems with K+.
What you do need to ensure if you have high stocking levels, is that you perform massive water changes, and that when you do the water change, you scrub and rub and keep the tank + filter(s) immaculate. Get rid of as much fish poop and organic waste (brown detritus) as possible because that is what kills fish, causes algae and stunts plant growth in a high tech tank, not inorganic NO3.
Cheers,