Hi,
Unfortunately this does not depend on the back-end options, the code is executed after the search process is finished.
If you want, you can add temporary FTP access and I can take a look at the code, maybe I can adjust it. Although I don’t know if there is a solution to be honest. The term ordering solution within the WordPress core is also pretty problematic code, and it does not work when the term search argument is passed either – so unfortunately I can’t re-use that for a solution.