After creating a custom property in toolbox and assigning a value to it, I exported the component's data to excel.  The custom property appears in the excel spreadsheet with the value the same for each item (each row).  I then add a formula to each row in the custom properties column.  The value updates correctly.  I then go back into "Toolbox" and import the new data.  The custom property updated correctly for each row.  I saved, then exited Toolbox.  Upon re-entering Toolbox, the custom property was replaced with the original data that I had entered.

How do I keep my data from being overwritten?