As you aware, Export in Excel Simple format is deprecated.
It is not available from version 5 onwards.
What you are not aware, probably.
For those who were using it in earlier versions, please take note.
If you are going to open and edit your old version report with the new version Report Designer.
It is going to kill your Excel Simple Export settings irreversibly.
Therefore, please make sure using Old Report designer to correct/edit Older versions reports.
Other words, there is no compatibility in the future versions of report designer with the older versions of the software. You can not edit and save reports of version 3.00 by report designer from version 5.00
It will spoil the report.
All the best,