Error: The Pokéarth page for Turnback cave has incorrect levels for platinum, and neglects to have show Dusclops being found in between the Entrance and first Pillar. The levels between those two locations are correct, but those between the first and second pillars are 10 levels higher than they truly are, being in their twenties level wise. Same with those between the second and third pillars, being in their thirties level wise.
Link: http://www.serebii.net/pokearth/sinnoh/turnbackcave.shtml#pt
I stated this before, and I have pictures of finding a Lv.16 Dusclops in Platinum.
I took that picture after finding one in my Japanese Platinum. I have also found one in my English Platinum, so I'm severally doubting that its just a glitch.