For the moment, Windward only accepts hardcoded format in the "Format" property of OUT tags.
We have a concern because our documents (MS Word) are produced for a lot of countries and languages, making the formatting of the outputs quite a challenge. With hardcoded formats only, we are unable to change the format according to our needs.

Hence allowing the "Format" property to use variables would solve — or at least alleviate — the issue, by allowing us to use a format that is not fixed in advance but could be changed in every document depending on data.

For the moment, only the OUT tags have this "Format" property. It would be great to add it also to SET tags, as specified in this idea: https://windward.uservoice.com/forums/248503-windward-core/suggestions/46954648-add-format-to-set-tag