Currently the column sum function is a very simple "add all the values together" calculation... and this is fine, for some uses. However, when trying to create things like weighted averages for stackable metrics like Visits or Unique Visitors, there is no proper options available to us.
If you want to use the total visits or total unique visitors for the period in the math, it will always be inflated at this time.
Why is this feature important to you -
This will provide more controls to being able to use the data the way you need to. Since the column "totals" already show the de-duplicated values, we should be able to create within the same table a representation of that number.
How would you like the feature to work -
This could work in two ways, either add some additional settings on the existing "column sum" function (particularly for "stackable" metrics), allowing us to choose either a "full sum" or a "de-duped sum"; or have another function that represents "column total" (and replicates the de-duped column total (before the dimension breakdown)
Current Behaviour -
Column sum does a generic sum of the values, adding up each row... but offers no way to de-dup stacking metrics like Visit or Unique Visitor... there is no way to use the de-dup "totals" shown in the freeform table as part of calculated metrics when attempting to created weighted averages.