In Manage | Database | Fields, make sure that your description field is of type text and not number.
It looks Odd that you have two fields on your layout that appear to be identical copies of the description field here...
The lower identical field is the internal::Description field whereas the upper identical field is the imported::Description field. It does look odd :)
You nailed the problem. In the internal table 'internal::Description' was set to number format. I switched it to 'text' and the output in XLS was as expected.
I'd certainly love to know why TAB and CSV formats produced different results... but, thank you for isolating the cause of the problem.
Tab and CSV exports generate text files. All field data, number, date and text, is converted to text for export. This conversion process exports all the data in the number field even if it is not unique. Excel file exports use the data types defined for the FileMaker fields to control the data type settings of the Excel cells of the file created by the export, so this different process does not export the non numeric data in a format that's visible in the Excel file.
Ah, that's what I thought. I was surprised that XLS and CSV had the same data and TAB was different. If anything, I would have predicted that TAB and CSV would have produced the same export (being text files) and XLS would be different (being binary).
Thanks again :)