Again, there seems to be no consensus with flushing.
What you're saying sounds logical, but I've done plenty of experiments, I never feed higher than 1.3, usually closer to 1.0 - 1.2ec under HID lights, and always keep runoff within 0.2ec or so. I consistently got a cleaner burning product with a water only finish in several types of media. Tried tapering back and not flushing for numerous crops with disappointing results.
I think it's important to say that I'm exclusively a joint smoker and use thin slowburning papers. For me flushed weed burns white/grey ash and the joint doesn't burn out, it has good heat retention in the cherry, and the flavour is maintained down to the roach. All the crops I did without flushing, the pot would burn out frequently and not leave nearly as clean of an ash, and lose its flavour halfway through a joint
But this subject seems to be subjective. Growers gotta experiment with it themselves and do what makes them happy.