Friends who often do contracts should have a certain understanding of "position management". When you transfer USDT or a certain currency into the contract account, this is your contract position, and the principal of each position should not be changed with the increase or decrease of your contract position.
For example:
I transferred 1000U (contract position) into the contract account, and planned to use 150U as the principal to open a position (position principal). I opened a position three times (or twice) in the order area, with 35U for the first position and 35U for the last position, and 80U for the last position. In this way, one position is completed. (Reducing positions in batches is the same)
If I have a profit of 100U, then my contract position will increase to 1100U, but the order is still 150 as the position principal, and the position principal will not be increased with the increase or decrease of the contract position. In this way, after long-term operation, if the winning rate is good, the profit and loss will offset each other and there will be no profit taking. Until the contract position grows to 3000U, consider increasing the position principal to 300U.