Blue Spiroc Proven resisted 6 enveloping roots out of 7 casts. Just a guess but it seems like the resists are about 5 levels too high....ie a blue mob one or two levels below you is resisting like a mob 4 or 5 levels higher then you would.
http://img263.imageshack.us/i/eq000006.png/
10 casts 6 resists 60%
Next pull was a light blue Spiroc Watcher
http://img222.imageshack.us/i/eq000008.png/
9 casts 5 resists 55%
Hope this helps guys, just trying to give you good documentation.