Ucbalumnus has it right.
Also at my school at least there is one threshold (I’m guessing 3.0 - they don’t tell us explicitly) that gets you thrown in the trash without human eyes and is school blind and another (Guessing 3.6 - also school blind) that just puts you in a later wave of review where human eyes will eventually see the app. After the 3.6+ group gets read the 3.0-3.5 group gets read.
The committee letter explains the grading system but human eyes need to read it to have an impact.