I think the idea is that right now, during creation, we're allowed to make an item or items that would set us back a level...but that -during play- the standard rules apply. That is, this is now or never. Blow the exp now...because you won't be allowed to once we start.
Makes more sense that way, ar?
Wrahn, I've got a question for ya...and believe me, I dunno how I became the designated nitpicker on design...

The Monk's belt description never says it grants the Wis bonus to AC, and I know I've never played that it does. The last line is crucial, I think.
"This AC bonus functions just like the monk’s AC bonus."
The monk's AC bonus is that +1 untyped bonus to AC that monks get at level 5, and goes up one every 5 levels. At least, that seems reasonable to me, given the cheap cost of the belt. 13,000gp for a slotted item that gives infinitely stackable +1 to AC, raises unarmed damage, works in conjunction with monk class abilities, but doesn't -require- you to be a monk... That's pretty darn decent.
But if you factor in the whole, "Oh, and you get Wis bonus to AC too," then I think 11,000 is pretty grossly underpriced. Granted, the item description doesn't specifically rule it out...though I think that last line comes pretty close to doing that. A case could be made though that "the monk's AC bonus" includes Wisdom bonus. Hence the confusion.
Still...if so, it's gotta be the cheapest AC increasing item in the entire D&D panoply of stuff.
Thoughts?