Count missing tick

Dear cTrader,

My robot has long code inside OnTick() event, so I afraid that it will missing some tick coming, and cause bad trading. How can I know my robot missed tick or not, and how can I count how many tick lost? Which method or event I shouldn't use in OnTick() to have best excute time?

Beside that, I use

if (!Positions.Any(x => x.TradeType == TradeType.Buy))
{
   // close Long pos
}

to determine TradeType and close the Position.

I also use

if (!HavePosition("Buy"))
{
   // close Long pos
}

....

        private bool HavePosition(string tradeType)
        {
            bool PosCount = false;
            int numPos = Positions.Count - 1;
            if (tradeType == "Buy")
            {
                for (int i = 0; i <= numPos; i++)
                {
                    if (Positions[i].TradeType == TradeType.Buy)
                    {
                        PosCount = true;
                        break;
                    }
                }
            }
            return PosCount;
        }

that have same job, determine TradeType and close the Position.

My question is which code has better excute time?

Thanks!