I know what you mean. Last year most of the teams had two cars, but this year they're down to one and the organisers have a spare that they let a team use if its car has been damaged beyond immediate repair.
The rookie sessions are not worth much, in my opinion, so far as comparing drivers' speed is concerned. Most of the teams use the session to do what I call housekeeping duties, i.e. getting the car in shape for the main sessions later on. It's not very often that a driver is let off the hook to set a time.
Sorry about your weekend. I reckon the car was not really 100% after the big roll at Eastern Creek. James Hinchcliffe is better than that.