I think the way that the numbers work ie 20-20-20 is for when you use the max strength for the amount of water that they say to use the amount in. And if you add another nute and find out the numbers I think it does add up like that.
The N-P-K numbers signify the ratio of the 3 macronutrients, but you control how much to add to a given volume of water. The actual numbers are the % (by weight) of each. For veg you want higher N, for flowering higher P. I'm going through some calculations now because I planted in MG soil (this is my first grow) and I need to add P and K for flowering. I'm working out the numbers for K2HPO4 to see how much to add to my water - anyone done this? No sense in re-creating the wheel!
So if they are ratios then would 2:2:2 = 1:1:1 in percentage of each and overall amount of net nutrients or is the total amount of combined nutes greater in 2 than 1?
Wicked lit right now so I don't know I worded that question right.