Ah, ok, that I noticed as well but didn't think of it, in my heroic will of emperor, the boss phase lasted 1 min which means 100k dps just cause they were 2, while I can't break 60k ST.
Also got feng 25 hc down, someone had already done it and nothing special, quite disappointing breath uptime (max 1 min 20 per breath), still beat enrage by 15 sec and it's survivable for a while anyway; managed however some breath of over 2 mins at last in my stone guard 25 hc again today and some ji'kun 25 hc attempts.
Too bad the nerfbat is incoming soon for breath, I think 20 rp per sec is really asking too much, aside from when you get lucky multistrike streaks, given that abilities which give most give 20 as blood and 24 as frost.