Set pa, key set pa and crowd pa jobs

There seems to be quite a discrepancy between set PA, key set PA, and crowd PAs as far as whether they belong in Assistant Directors, or Additional Crew sections. (PA meaning, of course, production assistant). I did a down and dirty check on these three jobs, and here are the results. They include most variations of the job:

Asst Directors   

set pa............5092

crowd pa........1072

key crowd pa... 62

key set pa.......690

Additional  Crew

set pa.........>40,300

crowd pa...........103

key crowd pa.......11

key set pa.....12,310

There's always a problem with this kind of data because you never know for sure whether the numbers really belong there or if they're in there incorrectly. It looks like set PA and key set PA overwhelmingly belong in Additional Crew, but crowd PA belongs in Assistant Directors. That doesn't make sense to me.

The only relevant section in the Help that I could find was in the Assistant Director section where it says, "Some lesser related credits should still be submitted to the additional crew section, such as runner, production intern, production assistant, and assistant to director."

So, where do you all think they go? Thanks.