When you starve your plant by flushing it does nothing to remove anything from the flowers. The fade people talk about when the leaves turn yellow is the plant moving nutrients from the leaves to the flowers. So in reality when you starve the plant by flushing it just cannibalizes itself. Nothing is removed from the flowers they still accumulate nutrients they just come from other parts of the plant. That is why the leaves turn yellow. Everything is sent to the flowers nothing is removed.
Flushing can actually be detrimental to the final yield and quality when you deprive the flowers of the nutrients they need to grow to their maximum potential.