You might try changing:
Code:
.Text = "\([A-Z0-9][A-Z&0-9]{1" & Application.International(wdListSeparator) & "}\)"
to:
Code:
.Text = "\([A-Z0-9][A-Z&0-9]@\)"
though I doubt that would make much difference.
Beyond that, I think we'd need to see an extract from the document demonstrating the issue. You can, of course, obfuscate any other content you wish to keep private.