Our PI program looks at 10 min from dispatch to liftoff for RW flights. Our pilots are generally in the air within 5 minutes. I've personally never seen anyone on our team question a pilot's response time. On one hand, we get anxious if a pilot appears to be "taking his time", but we also know that he is going through his preflight checklist and, through this formality, is being safe. In general, we notice the slower response times when a pilot is new to the team. As his comfort level with the preflight checklist and the aircraft increases, his response time decreases. I'll get back to you to see if we have a policy on response times...I pretty sure we do, but unable to recall for sure.