There is a time difference when the software order arrives at the exchange server, and the price may be different from what you see when the trading order arrives. If you want to avoid it, don't use the market price, just use the specified price. Finally, it is recommended that you do not trade manually. This error will be great. It is best to place an order in advance and specify the terms of the transaction, that is, place an order in advance, so that once the price changes meet your requirements, the software will automatically execute the order, which is much more accurate than you manually.