My car 1.2 TSI Octavia (2011) also demonstrates this behaviour after an upgrade they did.
Normal start (in the morning) is about 1000rpm and 1,2 l/h and then drops in less than minute to 800rpm and 0,8l/h.
http://www.youtube.com/watch?v=nuAJGxHCKac
But when the outdoor temperature goes up (sunny day and car is parked outside) then it starts witn 1200rpm and 3l/h and stays there - I havent had teh patience to wait when it drops. When I drive a liitle it goes pack to normal idle rpm.
http://www.youtube.com/watch?v=5-zXtjrjwQg
I went to dealers and they said that it is not a problem but a feature. But they could not explain why it is needed.
I would understand that this happens in cold weather but not the other way around.
Could anybody explain why it is useful?