WL6-Sum-Value-missing-in-WL7

I notice that Sum.Series has been moved to the TimeSeries as the Sum method. I don't see an equivalent Sum.Value. Is it available??

I'm building an index in PreExecute and I want to use the Sum(period) of the bar (idx) in Execute. Currently I have to call MyIndex.Sum(period) in Execute to get the single value. For efficiency, I'd like to be able to get the single value.

This is what I'm doing now...

CODE:
      public override void Execute(BarHistory bars, int idx)
      {
         TimeSeries tsBasketSum = _tsBasket.Sum(_spPeriod.AsInt);  //build entire TimeSeries
         int bidx = tsBasketSum.IndexOf(bars.DateTimes[idx]);

         _tsFundAvg[idx] = tsBasketSum[bidx];
         
         // Code for trading here.
      }

I was hoping to do something like this...

CODE:
      public override void Execute(BarHistory bars, int idx)
      {
         int bidx = _tsBasket.IndexOf(bars.DateTimes[idx]);

         _tsFundAvg[idx] = _tsBasket.Sum(_spPeriod.AsInt, bidx); 

         // Code for trading here.
      }