I'm sorry but, I assumed your "everywhere" literally meant every airport in the world, so I suggested to the Virtual Airlines override, which is in fact a global option.
Everything you reported is completely normal because:
- The Catering operator doesn't have any link to the Handling operator or the airline parking codes. It has its own separate scoring system.
- You happened to test all airports (KDCA, KLAS, KATL and KSAN) that all have only Southwest with the maximum scoring and, since your airport profile haven't specified any explicit operator for Catering, the default scoring is used, so all your results are normal.
Of course, through the Operator page, you can explicitly set any operator you like, on every gate, bypassing the default scoring system.