I put stuff 1,000 below supers every day....
We still don't fully understand wake. Remember that 777 that banked 45 degrees in severe wake turbulence from a 380 50nm ahead and 1,000 above a few years ago coming off the NAT westbound?
http://www.flyingmag.com/pilots-places/pilots-adventures-more/jumpseat-assaulted-a380