Stopwatch not giving accurate times

            List<float> uLSexI = new();
            tools.log("Unsorted Linear Search, EXISTING Item", ConsoleColor.Red);
            foreach (int increment in increments)
            {
                tools.log($"Increment {increment}");
                genItems(increment);
                item[] itemsUnsorted = items.ToArray();
                int existingQ = itemsUnsorted[random(0, itemsUnsorted.Length)].quantity;
                long startTime = Stopwatch.GetTimestamp();
                int indexFound = LinearSearch(itemsUnsorted, existingQ);
                TimeSpan elapsedTime = Stopwatch.GetElapsedTime(startTime);
                tools.log($"Increment {increment} complete in {(float)elapsedTime.TotalMilliseconds}ms ({elapsedTime.TotalSeconds}s)");
                uLSexI.Add((float)elapsedTime.TotalMilliseconds);
            }