Columns as Variables
When using a formula, you can assign a variable to reference another column in the structure, including another formula column.
To assign a variable to another column, look for the USED IN COLUMNS section in the Source drop-down.
Used in Column copies the existing column. It does not link to that column. This means:
You can remove the original column without affecting your new formula. The calculations will continue to work just as they did at the moment you first configured the variable.
If you update the original column and want that update reflected in your new column, you need to remap the variable.