Your understanding of the deposit needs to be more detailed. The price increase is easy to understand, and the deposit will increase accordingly. However, if the price falls, it is not in proportion, but in absolute value. For example, if you pay a deposit of 200, as long as the contract price falls by 200, that is, to 1800, you will be declared short. Before falling to 1800, you will either increase the margin or be forced to close the position by the futures company.

So in fact, you can understand that the deposit only increases.