Calculate sales/buys

Hi.

When I get the bars on the OnStart() method, I try to calculate if the Tick volume is from a sell (on the bid side) or from a buy (on the ask side). So, I do the following:

[Robot(TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
public class MyTakeProfit : Robot
{

blah... blah... blah...

        private Bars bars;
        private Ticks ticks;
        long sells = 0;
        long buys = 0;

        protected override void OnStart()
        {
            bars = MarketData.GetBars(TimeFrame.Tick);
            bars.Tick += Bars_Tick;

            ticks = MarketData.GetTicks();
            ticks.Tick += Ticks_Tick;

            for (int i=0; i<bars.Count; i++)
            {
                if (bars[i].Close == ticks[i].Bid)
                    sells += bars[i].TickVolume;
                if (bars[i].Close == ticks[i].Ask)
                    buys += bars[i].TickVolume;

                if (bars[i].OpenTime != ticks[i].Time)
                    throw new Exception("different times");
            }

            Print($"sells: {sells}, buys: {buys}");
        }
}

My problem is that the sales are always equal to the amount of bars.Count() which tells me that the closing price is always equal to the Bid price.

I would expect this to be wrong as we also have buys.

Am I doing something wrong? Maybe it is the demo account at Pepperstone or something?

Is it any way to calculate the sales & the buys? Maybe by looking the asks/bids going up/down compared to the previous ones?

Thank you very much for your help.

Efthymios