Yes, that is how I understand it. But I am also still learning about it. It was interesting to see the margin calls during the 40% price drop of the crypto market two weeks ago. Basically, before the drop some people had enough collateral above the 175% threshold, but during the drop these positions entered the margin call area and the orderbook of the decentralized exchange was automatically filled with USD buy orders, so that they were forced to close their position.