Your correct. If it's working, why change it.

I'm unfamiliar with what "moderate" means on an xbox. I wish I had one!

Port bypassing is something completely different than bypassing the NAT feature. If things are working, you don't need to to make any changes there. If you want a further explanation of how ports work, I have a great diagram at home from a course I taught that I could post. Basically though, it is not relevant for you at this time.

With great power comes Awesome irresponsibility.