Why not the same outcomes?

Hi there,
today i created my first EA. I just wanted to do a backtest for statistics.
My entry condition was:
1. Go long after a two-day higher close + exit on the next opening
2. Go short after a two-day higher close + exit on the next opening

Therefore i had only ONE code with the ONLY the Parameter OP_BUY to OP_SELL changed. As i have the same exit points, shouldn't i then have two contrary outcomes like, -2000$ for long and +2000$ for short?
Here's the code wich is in my start function:


int start()
{
//----
//variables
double open;
static int ticket, err;


OrderClose(ticket,0.1,Ask,3,Red);

if(Close[1]>Close[2]&& Close[2] > Close[3])
{
ticket=OrderSend(Symbol(),OP_SELL,0.1,Open[0]+2*Point,3,0,0,"buy on a 2day higher close",1,0,Green);
err=GetLastError();
if(ticket>0)
{
OrderSelect(ticket,SELECT_BY_TICKET);
MessageBox("Order opened at " + OrderOpenPrice(),"Order opened");
}
else
{
MessageBox("Error" + err, "ERROR!");
return(0);
}
}



Only the bold parameter was changed from short to long. So if i have a certain profit on the one backtest, shouldn't i have the same loss on the other backtest?
I hope you got my problem. Maybe i'm just confused, or i'm just overlooking something. Please clear things up, i'm struggling.
Greetings
-mike

BTW: How do i manage that i exit my position on the close of the same day. I mean in the example above i opend my position on the open of the day, but how do i exit on the same day (on the day's close)??

Hope you can help my in my two questions.
Cheers

The factor which you are missing is the broker spread. If your broker spread is set to zero then you will have the outcome of $-2000 and $2000 when you reverse the position.

Regards,
Mikhail

Yes but the broker spread is the difference between ask and bid price. And in my example above i didn't change the ask price to bid price. So i should have the same results, right?

edit:
Would somebody that kind to change the code in a way that, profit on the one "system" is equal to the loss "in the other system".

I'm now trying for hours to solve the problem, but i'm not able to handle it.
1. Is it right that, the strategytester only accept bid prices?
2. Or how is the connection between the bid/aks and buy/sell in the strategytester?
3. How can i produce the "raw" result, so that rofit on the one "system" is equal to the loss "in the other system"?
Thank you very much in advance!!
Greetings
-mike

With every trade you do you are still paying the spread. So for example the broker spread is 4 pips. Now say your OP_BUY was opened and closed with a 20 pip profit you then deduct the broker spread leaving you with 16 pips. Now say you changed the position to OP_SELL where you should lose -20 pips. But since there is a 4 pips spread you instead lose -24 pips. You see every time you take a buy position you buy at the ask price and every time you close the transaction you close this at the bid price. and reverse for sell orders.

I suggest you try coding your EA in MT3 where you can put the value of spread in strategy tester = 0.

I Also PM'd you a link to an article that may help you better understand your problem.

Hope that helps.

Regards,
Mikhail

Thanks mik, very helpful!