In soil flushing is a different story, but in hydro it isn't necessary and in fact hurts the quality of your final crop.
This notion that the plant 'stores chemicals' or 'stores excess food' is not correct. The chemical nutrient is brokent down at the root level and the plant absorbs only the nutrients it needs down there. It absorbs only what it needs to grow, it doesn't absorb extra to put it in a 'plant storage compartment.' When we eat, do we store leftovers in our body? No. Plants aren't that different. They don't have a 'camel hump' where extra food is stored. They don't.
Taste is acheived through proper dosages of NPK at the proper time and proper curing. Translocation and leaf apoptosis in late flower are natural processes of the plant that are promoted through the correct ratio of nutrient in the feed... not through plant starvation.
Flushing only promotes the plant to feed upon itself... so it's not at its best when harvested.