Does circle ci charges credits on the idle time in parallel mode

I’m seeing that my parallelism workflows have a huge idle time.
Not sure if Circle CI charges credits on the idle time or not.
I have looked through the doc and found nothing on this topic.

The example in the doc stated that for 2 parallel jobs with 1250minutes each will be counted as 2500 minutes against the credit but it didn’t talk about what if the jobs run with 1250minuts on one and 1200minutes on the other.