Confusion about oyster card travel extension permits?

I have no travelcard loaded on my oystercard, now from what I have gathered I will need no extension permit to travel with allowed national rail routes. Am I correct there? Problem is that the wording on tfl's website is awkward. On one hand they say you dont need an extension permit and than saying you do if it is not covered by your travelcard ( ignoring the case if you don't have a travelcard loaded at all)