Hi, in a previous post I've been suggested to code my rotational system using the regular backtester rules. This sounds great and in the following there is my attempt, but I'm experiencing a strange behavior on some trades. I'm surely doing something wrong but I can't figure out what and why this happens.

To debug my formula I've coded a simple version using backtestmode rotational and mimed the same system using the regular backtest mode.

**System rules**

- weekly rotations that occurs on each Monday
- trade the next day at open
- one asset (100% of equity)
- position score based on ROC

rotational backtest formula:

```
RotationDay = Param("day", 1, 0, 6, 1);
Positions = Param("Positions",1, 1,10,1);
ROCLB = Param("ROC LookBack", 1, 1, 100, 1);
SetBacktestMode(backtestRotational);
SetOption("MaxOpenPositions",Positions);
SetOption("WorstRankHeld",Positions);
SetOption("InitialEquity", 100000);
SetPositionSize(100/Positions, spsPercentOfEquity);
rocVals = ROC(Close, ROCLB);
IndRoc = rocVals + 1000;
IndRoc = IIf(DayOfWeek() == RotationDay, IIf(BarCount < ROCLB, 0, IndRoc), scoreNoRotate);
PositionScore = IndRoc;
```

regular backtest formula:

```
Positions = Param("Positions",1, 1,10,1);
ROCLB = Param("ROC LookBack", 1, 1, 20, 1);
RotationDay = Param("Day", 1, 0, 6, 1);
SetBacktestMode(backtestRegularRawMulti);
SetOption("MaxOpenPositions",Positions);
SetOption("InitialEquity", 100000);
SetPositionSize(100 / positions, spsPercentOfEquity);
SetTradeDelays(1,1,0,0);
BuyPrice = O;
SellPrice = Ref(O,1);
rocVals = ROC(Close, ROCLB) + 1000;
// Rotational Logic
DOW = DayOfWeek();
tomorrowDOW = Ref(DOW, 1);
Buy = DOW == RotationDay;
Sell = tomorrowDOW == RotationDay;
Buy = ExRem(Buy, Sell);
Sell = ExRem(Sell, Buy);
PositionScore = rocVals;
```

**THE ISSUE - example**

In the following image you could see that every trade of the regular formula is identical of their corresponding rotational one, except the one on CRM:

Looking at the chart, it seems that for any reason, instead of considering the "sell day + 1 open price", it considers the "sell day + 0 low price". Look at these images:

ROTATIONAL : ok

REGULAR : wrong

This slight error produces big result differences:

What I'm doing wrong here?

Thank you a lot for any help