I seriously doubt any H in australia is 90% purity, no one would come across that pure H and not cut it down a bit to make more money. Also if you're only going off anecdotal evidence and have only picked up heroin once, how can your opinion mean anything? The australian crime comissions purity testings show that it obviously sits around 30% these days, and in the heroin peak in 1999 (where you could go to a certain SW sydney suburb and get a fairly pure heroin cap for lower then the current price per point) it shows it was around 50%, which seems to check out, so I think their data is reliable when it comes to purity, as they would have obtained a large amount of samples from various parts of australia.