Calculating Indicators

I can write Moving average indicators two ways (see below) but when I backtest I get different results. Should the results be the same?

Method 1

public class MyAlgorithm : QCAlgorithm
{

        ExponentialMovingAverage ema;

 //Initialize the data and resolution you require for your strategy:
        public override void Initialize()
        {

               ema = EMA(symbol, 200, Resolution.Minute);

        }

//Data Event Handler: New data arrives here. "TradeBars" type is a dictionary of strings so you can access it by symbol.
        public override void OnData(Slice data) 
        {   
             foreach(var bar in data.Values)
             {
                 if(bar.Symbol == "my symbol")
                {
                       //some logic using the ema for this symbol                

                }

             }

        }

}

Method 2

public class MyAlgorithm : QCAlgorithm
{        

        ExponentialMovingAverage ema = new ExponentialMovingAverage(200);

  public override void Initialize()
        {

             // no need to initialize. The data is again minute resolution

          
               AddSecurity(SecurityType.Equity, symbol, Resolution.Minute);
            

        }

 //Data Event Handler: New data arrives here. "TradeBars" type is a dictionary of strings so you can access it by symbol.
        public override void OnData(Slice data) 
        {   
             foreach(var bar in data.Values)
             {
                 if(bar.Symbol == "my symbol")
                {
                    ema.Update(Time,data[bar.Symbol].Close); 

                   //some logic using the ema for this symbol
                }

           }

       }

}