I added an X-step pretty early on, just seemed pretty natural and led to more distance. That being said, I find I get better accuracy from a stand still - I think that's true for most people, there's just less moving parts, so to speak. On fairways where placement really is more important that distance, I tend to take a single step into my throw, and not a full X step. I'll gladly sacrifice distance for a decent lie on my 2nd shot.
Not familiar with the classic Roc, so I can't speak to that. But people who are familiar will want to know how far you're throwing it to get it to turn right. Every disc will turn at some speed. The more stable and/or faster a disc is (two differnt things actually) the faster the disc must be travelling before it will "turn over" or "flip." Less stable and slower discs will flip at a slower flight speed.
So how far your getting it out there before it turns is relevant. could be you;re getting pretty much all it;s designed to do, or it could be quite broken in.