You cannot bill incident-to on the first visit, or for a new problem, so the PA would not be seeing the patient in either of those two scenarios. There are no "incident-to guidelines" as you said, that state that has to occur. In fact, you wouldn't need incident-to if the MD were seeing the patient every time.
If you are talking about followup visits, then the MD doesn't need to see the patient for incident-to.
When we had a PA, rarely would both the MD and the PA see the patient on the same day. It usually only happened when the patient's condition had worsened greatly since their last visit, and the PA would ask the doc to come see the patient in the room. Then you would add the time together for both. But in both of your posts, you are describing both providers seeing the patient as a matter of course.
Also, as I said, the new E&M is not only for Medicare. It is changes in the CPT codes put out by the American Medical Association, so it applies to anyone who uses CPT codes.