Wheels do their acceleration times 2-up with at least half a tank of fuel, and it seems they won't keep trying until they believe they have the best time. Motor try to get the best times, and (WRX style) don't mind trying to kill the car to do it. 6000rpm clutch dumps in a WRX will pull a sick time, but you can only do it 5 times till you need a new $700 clutch.
You can only realistically compare car magazine times on the same day at the same track. Most of the FG times so far were all timed on the Ford press release of the FG, Ford wouldn't be too happy with the press flogging the living crap out of their cars on their first time out.
Oh yeah, IMO comparing random times from random car magazines is fucking gay, and ultra AFF spec. If you think that's offensive, I suggest you complain to
http://www.fordforums.com.au or the like.