erubin, I disconnect the O2 sensor underneath the car. The duty cycle read 25%.

With O2 sensor connected, duty cycle is adjustable and my current setting is very close to 25% up and down. At 2500rpm, it leans to 30%.

I guess the answer is clear to me now. I think there's nothing wrong with your Actron. Our cars are supposed to behave like this, like andengines has described.