next trying take profit

the idea:

take profit on a buy trade: on the low 3 candle bars before the trade open candle

take profit on a sell trade: on the high 3 candle bars before the trade open candle

am i on the right path? or complete off?

            var TakeProfitBuy = MarketSeries.Low.Last(3) - Symbol.PipSize * TP;
            var TPBuy = Math.Round((Symbol.Ask - TakeProfitBuy) / Symbol.PipSize);

            var TakeProfitSell = MarketSeries.High.Last(3) + Symbol.PipSize * TP;
            var TPSell = Math.Round((TakeProfitSell - Symbol.Bid) / Symbol.PipSize);

thanks,

Jelle