One approach is to return 0 if the sum of savings for all products == sum of savings for those in the view. To get an unfiltered value for sum of savings, you can use rawsql.
For example, in the Superstore data set, you can find the total sum of sales---direct from the data source and independent of filtering---using
Sales TOTAL = RAWSQLAGG_REAL("SELECT SUM([Sales]) FROM [Orders$]")
Now you can create another calculated field to return 0 if sum of sales in the (filtered) view == (unfiltered) Sales TOTAL.
Sales -- 0 if all = IF [Sales TOTAL] == SUM([Sales]) THEN 0 ELSE SUM([Sales]) END
Note that RAWSQL functions are not supported in extracts.