What you guys are missing is that plants don't eat/feed at all. Plants create food (sex organs) for all animals including humans, from basic elements. Circle of life... They only need 'enough' of those elements in their root zone , more than enough only accumulates in leaves and stems and does not result in more fruit (bud). Staying on the low end also is a lot easier on the roots, which in turns makes it easier to take up all the nutrients they need.
And you cannot determine the nutrient need of a plant by the ppm going up and down alone. Common (forum-)misconception. If the ppm stays stable it merely means only that the total amount of nutrient uptake and water uptake is balanced. It says little to nothing about the 'need' of the plant. The need is full-filled far below that sweet spot.
And no, you don't get more yield from higher ppm. Like I said, the genetically limited maximum yield potential is reached with 'enough' nutrients. Any more can quickly lead to adverse affects (most problems in this forum...).
As for faster vegging... the difference is minimal. Posted my ridiculous fast vegging in a thread about a month ago.
Lucas formula... please... don't get me started.
Let the plants tell you what they want,
Exactly. The plants, not your ppm meter.