Answer
A development program exists for this on the long term roadmap.
In the meantime, the files (Excel or SUSHI) can be downloaded, deleted and re-uploaded. This should be done in the following order:
1) From the "Uploaded Files" screen, find the problematic file.
2) For each file, click on the "File" link, and save the file to your computer (set aside a folder for this).
3) After the file is downloaded, edit it (outside of UStat)
4) Delete the file in UStat
5) Upload a correct file
