I am sure anyone who started a character noticed the NPC says don't overlevel because you won't get your sp back. In other servers (including GMS I think) you can overlevel and finish all the quests and get all the cool stuff from them. So why not here?
But still-you can't get the cool potions from the last mission there without Overleveling. And many other missions and stuff.
The quests was designed so yoy could do them all without overlvling them, you just got to know the system.
I tried it but if I would have done the quest of getting a mushroom cap I was already overleveling. And I had 90% xp!
I tested this when the rates for level one through ten were reduced on the island. By doing all quests with minimal monster interaction, I reached level nine with about eighty per cent, if memory serves. I did not reach level ten, at any rate.
The one quest that might run the risk of overlevelling you is completing "Biggs's Story on Victoria Island at Olaf in Lith Harbor if you reset the rates to 4x exp first.
Even after doing that what as well as the introduction quest for classes that gives 1200 XP once you talk to your job instructor will give you around 40% into level 10. Just attack only when given quests and you should be fine.
