You're doing it wrong, I was at 100 available, and I've gone from 10-45 so far off of roughly 50 of 'em. Make sure to always turn in HQ items, and the leves from the adventurer's guild in town are the ones you should be doing. Every craft I've leveled has a level 35 leve that will reward ~100k on a 1 HQ item turn in.
OT: They need to get on that immediately. This thread, the one on reddit, and the one from earlier are bad though. Just report it to SE, do not advertise things like this in threads.
You didn't explain how it's done, which is good, but I'm sure these threads have some people searching frantically for this exploit who would have never known this existed otherwise.
