Comments on existing version & Suggestions for future versions. If you want a new feature suggest it here. Discussions about beta versions also come in this section.
Calculate, yes, but do what with it then ?
Currently it is not possible to show it like that in the main window or use it in the export. It may be possible to use it in printed reports, since there is a script tool integrated in it.
As I said it is not possible in export with the program itself.
It is probably possible with the templates that use PHP or XSL (if I remember well, some of Twink's templates use that) but I can't help you
The script tool that I mentionned is for printing, not exporting.