关于可用资金的问题

我发现Portfolio_UsedMargin + Portfolio_CurrentCapital 不等于 Portfolio_CurrentEquity ，这是为什么？ //计算可用金额对应最大仓位（真实价格） Numeric calcAvailableSize(Numeric price,Bool islong) { // 按合约成交金额比例计算保证金 if(mRate.ratioType == Enum_Rate_ByFillAmount) { // 账号金额保证金最大持仓 Numeric MRatio = IIF(islong, mRate.longMarginRatio,mRate.shortMarginRatio) ; Commentary("!!!MRatio:"+Text(MRatio)); Integer pos_available = IntPart( (Portfolio_CurrentEquity - Portfolio_UsedMargin) / (ContractUnit * BigPointValue * price * MRatio) ); Commentary("!!!UsedMargin:"+Text(Portfolio_UsedMargin)+",CurrentCapital："+Text(Portfolio_CurrentCapital)+",Equity:"+Text(Portfolio_CurrentEquity)+",sum:"+Text(Portfolio_CurrentCapital + Portfolio_UsedMargin)); Commentary("!!!sum-roll:"+Text((Portfolio_CurrentCapital + Portfolio_UsedMargin)/Rollover)); return pos_available; } return 0; }