That would only work when exporting to Excel Data Only - although you would end up with both the two-decimal column and the six-decimal column.
If you suppress the column in the design it won't export. So here's what I might do:
1. Add the field to the report.
2. Format the number.
3. Make the font white (or whatever the background color for your report is).
4. Line up the field correctly for a clean export to Excel.
5. Make the field very narrow so that it doesn't take up space on the screen.
6. Place the next field against the right-edge of this field so that you get a clean export.
-Dell