Flushing is done and than the plant goes through the drying out process.
OVER Watering is keeping the plant roots in constant moisture so it never gets a chance to dry out, that's what kills plants. They die because the roots drown in the water after the dissolved oxygen is gone.
Big difference.
Just cut back you nutrients to 50% for the last 2 weeks and you don't need to flush, curing is where most or the magic happens.