flushing isn't a concern because it's an urban myth as far as blindly doing so without cause at end of grow. don't make decisions based on that.
is it exhiviting signs of toxicity? That'd be a reason to reduce or give water only, but unless it's a pending catastrophe, flushing is still 100% unnecessary.
If the plant is using what you provide (i.e. no toxicities building up), why would reducing or removing building blocks for molecuels that include THCa and every terpene possible and cellular reproduction help? It makes no sense. tests prove it has zero impact on mineral content of flower.. so if it is contructed and constituted the same way regardless, what exact is the cause to a positive effect that is occurring?