[amibroker] In regards to an Amibroker example

[readshark]

In the attached example from, http://www.amibroker.com/guide/h_pyramid.html.

Can someone explain to me why this is used "Buy[ i ] = sigScaleOut;".  I feel 
like I understand everything else that is going on here, but should it not be 
"Sell[ i ] = SigScaleOut;"?  What am I not understanding?

Thank you in advance.



Buy = Cross( MA( C, 10 ), MA( C, 50 ) ); 
Sell = 0; 

// the system will exit 
// 50% of position if FIRST PROFIT TARGET stop is hit 
// 50% of position is SECOND PROFIT TARGET stop is hit 
// 100% of position if TRAILING STOP is hit 

FirstProfitTarget = 10; // profit 
SecondProfitTarget = 20; // in percent 
TrailingStop = 10; // also in percent 

priceatbuy=0; 
highsincebuy = 0; 

exit = 0; 

for( i = 0; i < BarCount; i++ ) 
{ 
   if( priceatbuy == 0 AND Buy[ i ] ) 
    { 
       priceatbuy = BuyPrice[ i ]; 
    } 

   if( priceatbuy > 0 ) 
    { 
       highsincebuy = Max( High[ i ], highsincebuy ); 

      if( exit == 0 AND 
          High[ i ] >= ( 1 + FirstProfitTarget * 0.01 ) * priceatbuy ) 
       { 
         // first profit target hit - scale-out 
         exit = 1; 
         Buy[ i ] = sigScaleOut; 
       } 

      if( exit == 1 AND 
          High[ i ] >= ( 1 + SecondProfitTarget * 0.01 ) * priceatbuy ) 
       { 
         // second profit target hit - exit 
         exit = 2; 
         SellPrice[ i ] = Max( Open[ i ], ( 1 + SecondProfitTarget * 0.01 ) * 
priceatbuy ); 
       } 

      if( Low[ i ] <= ( 1 - TrailingStop * 0.01 ) * highsincebuy ) 
       { 
         // trailing stop hit - exit 
         exit = 3;    
         SellPrice[ i ] = Min( Open[ i ], ( 1 - TrailingStop * 0.01 ) * 
highsincebuy ); 
       } 

      if( exit >= 2 ) 
       { 
         Buy[ i ] = 0; 
         Sell[ i ] = exit + 1; // mark appropriate exit code 
         exit = 0; 
         priceatbuy = 0; // reset price 
         highsincebuy = 0; 
       } 
    } 
} 

SetPositionSize( 50, spsPercentOfEquity ); 
SetPositionSize( 50, spsPercentOfPosition * ( Buy == sigScaleOut ) ); // scale 
out 50% of position