That is a classic symptom of leaky valve guide seals. In my opinion, it is not critical. I would wait until you had some other need to crack those valve covers.
What happens is when you park your car for an extended period of time, the oil trapped on the top of the head leaks down past the valve guide seals and into the combustion chamber. There isn't a lot of oil sitting on top of the head, so you won't get any more oil than what you see burning already no matter how long it sits.