This has been solved! For other users who may be curious about how I figured it out, please see below:

Basically, the first thing was that I had to deactivate then delete my current version of the plug-in (while making sure that the “Remove all data when deleting Search & Filter” in the settings did NOT have a check in it). Then I installed the recent version of the plugin. After this happened, I had 404 messages on a few of my results pages, but all I had to do then was insert the correct results URL in the “Display Results” tab.