Sukenari use to have a water quenched AS damascus line. At their factory Hanaki san showed me the HRC test result for their AS line and the HRC was even higher.
The argument from Hanaki-san is that, as a blacksmith it is always his job to HT the steel to its maximum potential. However, by doing this, the failure rate as also prohibitively high: we are talking about 50%+ failure rate. Eventually he had to discontinue the line.
I suspect Mazaki is also experimenting with different steels and I doubt the AS output will be half decent.