给你看实际操作例子吧（这是我的Tiered交易费用):
TradeLogEntry(time=datetime.datetime(2021, 4, 23, 15, 40, 24, 849568, tzinfo=datetime.timezone.utc), status='Submitted', message='Fill 343.0@11.66')
TradeLogEntry(time=datetime.datetime(2021, 4, 23, 15, 40, 24, 849568, tzinfo=datetime.timezone.utc), status='Filled', message='')
CommissionReport(execId='xxxxxxxxxxx', commission=0.721182, currency='USD', realizedPNL=0.0, yield_=0.0, yieldRedemptionDate=0)
NKLA,fullFilled:343.0, avgFillPrice:11.66, commission:0.018%, market_order_loss:0.000%
Fixed的话是0.005每股， 相当于343*0.005=1.71美元
差别明显。
另一个例子：
TradeLogEntry(time=datetime.datetime(2021, 4, 23, 15, 10, 22, 999565, tzinfo=datetime.timezone.utc), status='PendingSubmit', message='')
TradeLogEntry(time=datetime.datetime(2021, 4, 23, 15, 10, 26, 131392, tzinfo=datetime.timezone.utc), status='Submitted', message='')
TradeLogEntry(time=datetime.datetime(2021, 4, 23, 15, 10, 26, 131392, tzinfo=datetime.timezone.utc), status='Submitted', message='Fill 68.0@58.31')
TradeLogEntry(time=datetime.datetime(2021, 4, 23, 15, 10, 26, 131392, tzinfo=datetime.timezone.utc), status='Filled', message='')
CommissionReport(execId='xxxxxxxxxxxxxx', commission=0.282257, currency='USD', realizedPNL=0.0, yield_=0.0, yieldRedemptionDate=0)
SNAP,fullFilled:68.0, avgFillPrice:58.31, commission:0.007%, market_order_loss:0.034%
Fixed的话是0.005每股， 相当于68*0.005=0.34美元，但是fixed最低1美元，差距明显。
所以总结就是， Tiered绝大多数情况下手续费比Fixed好很多。
