revs gears

Hi, I wonder if anyone has experienced the same...? I recently bought a new A5 Sportback 3.0 tdi Quattro, S' line. When the car is idling and stationary it is ticks over at around 500-600 revs not at the 1000 rev mark as in my previous Audis. I have the auto/tiptronic 7 speed gearbox and in...