A few hours ago I derped around StoneSkySea OV4S for about 45 minutes w/MCH checking my DPS. A low of 4000 (5 secs left) and high of 4300 (17 secs left). Same rotation EVERYTIME with the only variable being crits and procs. Stopped for a few hours. Just now out of boredom I derped around again with the same rotation for a half hour or so, but all of a sudden I can barely clear it. More often than not, failing it outright. Not getting crits, procs are few and far inbetween. Same gear, same rotation but not clearing. Whats going on?