Different result from tradingview in VolatilityStop index

the problem

hi, I noticed that in some cases there are discrepancies in the results from those calculated by the index and those presented by tradinview

to reproduce

Test code

var clinetBinace = new ApiClient_Binance();
            DateTime dateEnd = new DateTime(2020, 06, 01);
            var ohlcDays = clinetBinace.getOHLC(XtraCrypto_SymbolPair.BTC_USDT, TimeSpan.FromDays(1), endTime: dateEnd, limit: 300).ToQuote();
            var trendFast = ohlcDays.GetVolatilityStop(20, 2).ToList();
            
            DateTime[] dateTimesTest = new DateTime[]
            {
                new DateTime(2020, 02, 17),
                new DateTime(2020, 02, 18),
                new DateTime(2020, 02, 19),
                new DateTime(2020, 02, 20),
                new DateTime(2020, 02, 24),
                new DateTime(2020, 02, 25),
                new DateTime(2020, 02, 26),
                new DateTime(2020, 02, 28),

                new DateTime(2020, 03, 1),
                new DateTime(2020, 03, 17),
                new DateTime(2020, 03, 18),
                new DateTime(2020, 03, 19),
                new DateTime(2020, 03, 20),

                new DateTime(2020, 04, 1),

                new DateTime(2020, 05, 8),
                new DateTime(2020, 05, 9),
                new DateTime(2020, 05, 10),
                new DateTime(2020, 05, 11),
                new DateTime(2020, 05, 12),
                new DateTime(2020, 05, 13),
                new DateTime(2020, 05, 14),
                new DateTime(2020, 05, 15),
            };

            var trendVolatility = trendFast.Where(x => dateTimesTest.Contains(x.Date)).ToList();
            trendVolatility.ForEach(x => Console.WriteLine($"BINANCE - DATETIME: {x.Date}, UPPER: {x.UpperBand}, LOWER: {x.LowerBand}"));            
        

with this result

and this tradingview result. You can see that upper start from 19/02 but VolatilityStop start from 26/02

[DaveSkender]

We use the original “Volatility System” stop and reverse formula from Welles Wilder’s book New Concepts in Technical Trading Systems.

[DaveSkender]

@heavymanto, I’ll reopen this if you come back with a different conclusion after analyzing the above information and can arrive at a different conclusion.