No, AFAIK, that is for having the game capped at 10. I could be wrong, but I am almost 100% positive that is how that goes.
Yeah the default is set to 20, and you can make and save changes to suit your gaming style. If you have made some changes already, it's not going to hurt AFAIK to reselect LVL 20 levelcap and save, if that's what you want.