It’s never a bad idea to check whether you can avoid paying for something!
Porsche warranties do not cover oil changes—in fact, most car warranties don’t. In general, a limited or extended car warranty covers faulty parts in your vehicle that malfunction under normal use of the car. An oil change, however, is a maintenance service, and you are responsible to pay for it yourself.
In fact, if you fail to have your oil changed frequently and it results in damage to your Porsche, your warranty might not cover the repair, as this would mean you weren’t properly maintaining the car. So keep at it and stay on top of those oil changes!