//+------------------------------------------------------------------+
//|                                                       MATime.mq4 |
//|                                              Copyright 2023, AM2 |
//|                                     https://www.forexsystems.biz |
//+------------------------------------------------------------------+
#property copyright "Copyright 2023, AM2"
#property link      "https://www.forexsystems.biz"
#property version   "1.00"
#property strict
#property indicator_chart_window

#property indicator_buffers 1

input double k=1.2;
input string t1="10:00";
input string t2="20:00";

double ma[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
   SetIndexStyle(0,DRAW_LINE,0,2,Aqua);
   SetIndexBuffer(0,ma);
//---
   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=0; i<111; i++)
     {
      if(time[i]>StringToTime(t1) && time[i]<StringToTime(t2))
         ma[i]=close[i+1]+k*(close[i]-close[i+1]);
     }
//--- return value of prev_calculated for next call
   return(rates_total);
  }
//+------------------------------------------------------------------+

Можно и это как-то исправить?