Trader A uses USDT's order to purchase 0.4 BTC.
Trader B sold BTC and got 20000 usdt.
Receiver fee for trader a = 0.4 x 0.2% = 0.00008
BTC manufacturer fee for trader B = 20000 x 0.2% = 40 usdt
After the order is completed:
Trader a buys 0.4 BTC on a standing order, so he will pay taker fee of 0.0001 BTC. Therefore, trader a will receive 0.39992 BTC.
Trader B takes an order to buy 20000 usdt, so he will pay 40 usdt maker fee. Therefore, trader B will receive 19960 usdt.