Why is the cost of covering positions higher?

The position of the position is higher than the position price, and the higher the position.

The position of liquidation is lower than the liquidation price, and the lower the liquidation is.

Calculation method of stock increase and decrease cost;

Cost price after stock lightening = (buying quantity * buying price-lightening quantity * stock market price at lightening time)/remaining stock quantity.

Cost price after covering positions = (first purchase quantity * purchase price+second purchase quantity * purchase price+transaction cost)/(first purchase quantity+second purchase quantity)

For example, I bought 1000 shares at 1000 for the first time, 9 yuan increased its position 165438 shares, and 0 yuan reduced its position 1000 shares.