делим каждую разницу цены на номер вычисляемого бара

//+------------------------------------------------------------------+
//|                                                        Gisto.mq4 |
//|                                              Copyright 2018, AM2 |
//|                                      http://www.forexsystems.biz |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018, AM2"
#property link      "http://www.forexsystems.biz"
#property version   "1.00"
#property strict
#property indicator_separate_window

#property  indicator_buffers 2

double up[];
double dn[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
   SetIndexStyle(0,DRAW_HISTOGRAM,0,4,Lime);
   SetIndexStyle(1,DRAW_HISTOGRAM,0,4,Red);
   SetIndexBuffer(0,up);
   SetIndexBuffer(1,dn);
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
//---
   for(int i=1;i<1000;i++)
     {
      if(close[i]-open[i]>0) up[i]=(close[i]-open[i])/_Point/i;
      if(close[i]-open[i]<0) dn[i]=(close[i]-open[i])/_Point/i;
     }
//--- return value of prev_calculated for next call
   return(rates_total);
  }
//+------------------------------------------------------------------+