"RunHardwareBenchmark" returns different scalability values if run repeatedly

I’m using UE4.27.2.

I’ve hooked up an Auto-Detect button in my options menu. However, on lower-spec computers, the scalability values returned from “RunHardwareBenchmark” give different values after repeated presses of the auto-detect button.

For instance, if my scalability settings start at “Low” and I press the Auto-Detect button, the settings will update to “Medium”. Press Auto-Detect again, now they update to “High”. Press it again, they update back to “Medium”. Why is this happening and is there anything I can do to fix it?

Cheers.