You need to understand the rotations work in a quite simple way. Whenever a race ends (by voting to end race, by using /end, or when everyone disconnects), Airio takes a look into the rotation string. If it finds the current track there, it will move to the next one, optionally resetting lap count and/or car types, if specified. That is all, but it has some consequences:
1) If you're on a track that is not included in rotation string, ending race does nothing, there is no next track to go to.
2) If you do not have car types specified for next track in rotation, current cars will stay unchanged.
3) If you're outside rotated tracks/cars and want to enter (new) rotation, you basically do that manually using /track and /cars admin commands (or their Airio equivalents).