This is one of the most useful things I've ever learnt on this website.

There was actually an article about this here:
http://wow.joystiq.com/2010/12/14/zone-location-determines-living-elements-transmute-results/

Well it was a long time ago but I was also very happy to read about it on my favorite site and that's why my poor lvl80 druid was sitting on the edge of a cliff in Uldum, with lots of volatile life in his bags :) You dont even need the level requirement for Uldum, just fly in, find a nice sanddune, and the result is guaranteed.

Yeah, it is pretty nice guaranteed profit (I use it to make my dreamcloth, truegold, and enchants that require air a lot cheaper to make). The extra 4-6 transmute "procs" are of a random volatile type, however, no matter what zone you do them in.

You might also have lost track of that in all the swirl around how they reconfigured the transmute proc pretty early on.

Honestly, I should probably be playing the AH but I usually save my transmutes for guildmates because I've got more gold than I need - even if I'm not goldcapped. Plus I always seem to get burned on the AH whether it was Vanilla, BC, Wrath, or Cata. I suppose if I started reading the Undermine Journal a bit more, I might do better.