单向双向：某些产品的手续费只在开仓时收取，有些则在开仓和平仓时都收取； It is vital to compare P&L statements from distinct accounting intervals, as any improvements after some time turn into far more meaningful compared to numbers themselves. 今日持仓/昨日持仓：中国期货通常指定平今仓和平昨仓来收取不同的费用； La gente varía mucho a la hora de darse cuenta de lo que ve, escucha o sient... https://pnl41863.techionblog.com/34294021/details-fiction-and-pnl