I didn't get it at first either.
I figured it out after reading close-
How I (and most i feel like) feed, is by trying to get a stabil EC. That way we know the plants aren't getting too much, or too little.
In that scenario, if we topped up with a 33% solution, the EC would drop.
What the that guy is doing, is rasing the EC to the point where it slowly floats up because the plants are drinking more than they are eating. To me, I would lower the EC with straight water to stabilize the ec. This other guy, is topping up with 33% solution, and bringing it back down to the point where it will slowly float up again. In his method, he is looking for the EC to naturally rise.
I dont agree with that myself.... I dunno