Jobs report have the created by column, which displays the username of the job owner. In a project created from SP, the job owner is automatically the same as the default project owner set in the SP, even when the files are actually submitted by a different user (i.e. a submitter account).
The submitter is shown in the created by section of the project, but is not inserted in the jobs report.
Similarly to what exists for quotes at the moment, the client would need to add a Submitted by column to job reports.
This would allow monitoring who actually submitted files for translation through the SP.