I just realized I possibly wrote something that was a little inaccurate, simply because I chose the wrong words for it - quests don't increase the gil reward the higher the level you are, what I really meant to say is the higher the level of a quest you get, the more gil it will give, like, a level 50 quest will usually give far more gil than a level 10 quest. I just wanted to clarify that as I hope I didn't cause any misconceptions.