I don't even see the petals light up when watching them.
They don't really light up in any kind of timely fashion, they are more of a rolling average for the last I don't know how much driving. The only solid thing that I've seen is shifting my manual. If I accelerate hard and shift at the "red line" I will lose a leaf or two almost immediately. If I drive 200 miles without shifting again I will not gain those leaves back until I actually shift nicely another (dozen?) times.
I like it this way because it doesn't give you instant gratification so you think "I drove it like I stole it for the last 300 miles, but thats ok cuz I just got full leaves for 20 seconds".
The bad part is it's more difficult to learn what the car thinks is good behavior.
About the "cold starts", I don't think they have any bearing on the number of leaves as I always have the cold starts warning but I also constantly have full leaves. I just think you may not get the trophy screen.
