Help me how to show range bar time for second time scale.

I coding as below. It work well show previous period bar time by seconds.  But problem is that can't show real time last index bar accumulation total seconds. When i try it with last bar index and compare with server time utc than indicator breaks work and show below code.  Help me get trick for code. Best & Regards.

            TimeSpan TimerA = Bars.OpenTimes.Last(0) - Bars.OpenTimes.Last(1);
            if (TimerA.TotalSeconds < Save)
            {
                Green[index - 1] = TimerA.TotalSeconds;
            }
            if (TimerA.TotalSeconds > Save)
            {
                Red[index - 1] = TimerA.TotalSeconds;
            }