I tried few things and finally used Scope statement to achieve this. I'm posting my solution here which works across all measures. Please feel free to advise improving the current solution.
// Rporting Option //
Scope ([Reports].[Report Item].Members);
//Total Sales//
IF [Reports].[Report Item].CurrentMember IS [Reports].[Report Item].&[Total Sales] THEN
This = Sum({[Reports].[Sort Key].&[1]:[Reports].[Sort Key].&[2]})
END IF;
//Variable Contribution//
IF [Reports].[Report Item].CurrentMember IS [Reports].[Report Item].&[Variable Contribution] THEN
This = Sum({[Reports].[Sort Key].&[1]:[Reports].[Sort Key].&[3]})
END IF;
//Variable Margin//
IF [Reports].[Report Item].CurrentMember IS [Reports].[Report Item].&[Variable Margin] THEN
This = Divide(Sum({[Reports].[Sort Key].&[1]:[Reports].[Sort Key].&[3]}),Sum([Reports].[Sort Key].&[1]))
END IF;
//Gross Profit//
IF [Reports].[Report Item].CurrentMember IS [Reports].[Report Item].&[Gross Profit] THEN
This = Sum({[Reports].[Sort Key].&[1]:[Reports].[Sort Key].&[4]})
END IF;
// and so on for more for other report totals
END Scope;