Generally speaking, the settlement price is used to settle and control the margin account (for example, your margin is just enough according to the closing price, but if it is not enough according to the settlement price, you will be required to add margin), and the settlement price is also used to calculate the price of the price limit. The actual profit of your order depends only on the transaction price of your order at the time of opening and closing, and has nothing to do with the settlement price. The settlement price only affects the calculation of the rights and interests of the margin account when you hold a position overnight, and there is no actual trading behavior, unless you forcibly close the position at the settlement price.