[rant]
UGH!!!!
I don't mean to get angry, but this is exactly why, controls.dat never gets updated. You don't make your own personal tweak, you submit the changes!!!
Step #1. Go to
controls.arcadecontrols.comStep #2. If you don't have a login, make one.
Step #3. Click on Contribute, then Update a Game.
Step #4, Modify the existing submission and submit it.
Step #5, The next time the dat is updated the new entry will be there!
[/rant]
Ok griping aside.....
The asteroids entry was one of the very first we ever did. Back in the day mame had it hacked to use a 2-way joystick. Now it doesn't. So no it isn't incorrect, it's just incorrect NOW.

I will fix this one myself later, but for future reference controls.dat is a user dependant project. The reason it hasn't had any significant updates in ages is because nobody's bothered to do any user-submissons.
Also your gripes regarding cp wizard are a bug and you need to let HK know about it. Notice the "alternating=1" flag in game section of the entry? That is there to tell viewers that although it's a two player game, there is only one set of controls. Headkaze artifically injects start and coin info (the dat doesn't bother with those buttons) so the correct amount of them showing has to do with something on his end as well. It should be easily fixed.