Thanks for your responses.
From several postings here, I believed that the duty cycle should be around 50% with slight variations both at idle and at higher revs.
I have no particular problem, only some rough idle, something even stalls and the feeling that my car lacks power. I know that this adjustment has been touched, so I only wanted to be sure that everything is ok.
The 25% duty cycle sounds quite low to me, are you sure that this is ok?