The exp scale is 3x, but multi turn-in leves are 6 turn-ins instead of 3. This makes them really good for getting mats in some cases as the lv 52+ ones can have various things like lumber, nuggets, ingots, etc. Used to make a mint off holy cedar lumber that way, early on in 3.x they were 15k each and you'd get 60 from one of these grand leves.