For Internet Explorer 11, it depends on "Compatibility Mode".
If you are in "Compatibility Mode" via Intranet security zone, the export wizard columns accurately reflect what you select in step 2.
If not in this mode, your columns are off by increasing amounts as you work to the right of the report. NOTE: Putting the web site in "Compatibility View" alone not enough, it has to be Intranet zone too. For some reason (IE), compatibility view is different under the Intranet vs. non-Intranet.
Set your browser so Web Viewer (the web server) is in the Intranet Zone and
The compatibility view settings have "Display intranet sites in Compatibility View".
If already accessing Web Viewer while doing this, please log off and close the browser before retesting.