There is more than one "right way" to dose fertilizers. As much as anything, what made the Estimative Index method so popular, is that it isn't a rigid, set in concrete, system. The principles of it are simple and very liberating if you have been struggling to get just the right concentrations of each nutrient in the water at all times, using daily testing, milligram scales, precisely mixed solutions, etc. Once you accept that there is no harm in having a higher concentration of nitrates, phosphates, etc. in the water, than the plant will consume in a day, you have a lot of freedom for dosing as often as best fits your desired schedule. The only nutrient that is "tricky" is carbon. The most effective concentration of carbon, in the form of carbon dioxide, for high light tanks, is too close to the concentration that can harm fish, for you to be as casual with it. And, the concentration that doesn't harm the fish is too close to being too little to avoid BBA outbreaks for you to be casual with it. That's why it is best to concentrate on CO2 instead of to KNO3, KH2PO4, etc.