They aren't out of scope as much as they are irrelevant. It has been a best practice to ensure that the things you would be attempting to attack the timing of do not let you do this for a very long time. We are so far down this road that we do things like generate thousands of values and throw most of them away to mitigate the laziest attempts at what would be considered in scope.
It's still relevant (and probably also rather difficult) to prove that seL4 itself conforms to those best practices.