Thanks Gems.
Your thought would require that a trader is so perfectly in tune with the market that they KNOW that the price will drop to a certain place, so they are willing to forego their daily profits, to make more later when they buy back in.
Whales make a huge return on their investments (30% or more annually), so to try to time the market for a "maybe" is not that great of a strategy.
My guess is that the power downs are really very simply cash flow problems, plain and simple. Just like margin calls force people out at the worst possible times.
Blessings!