as you can see, this is twins normal. raid damage isnt that high. it could even be the kill from when their aura was inactive. rejuvenation did 83% overhaling. according to my previous calculations t8 bonus would increase rejuv's healing by roughly 70% (12% / 17%). however this instant tick did 50% overhealing too, decreasing bonus to 35-40%. but to be honest - is this log viable to judge anything? overhealing was so high that it doesnt really matter what set you were wearing. you could go there with t7 from naxx 10 man and drop 2 healers out and effect would be similar ^^
i think this would be more viable log:
http://www.worldoflogs.com/reports/r...?s=1907&e=2182
its one of our twin val'kyrs 25 heroic tries. im having t8 set here. you can see that healing done by rejuv ticks is around 60-65%, while instant heal is near 5%. overhealing done by rejuv is on 20-30% level, overhealing done by instant ticks is 10-15%. as you can see instant ticks increased my rejuv's healing by around 8%