i also notced that the fenrir has a single fan in push mode. Can it be that the tests were carried out with only a single fan setup?
If that were true, then the Hyper 212 plus is technically the winner as it capable of a push-pull setup
Well - Push/Pull is definitely worth a few degrees... *if* your motherboard has room for the second fan. My rig has a Thermalright Venemous~X, which also supports Push/Pull. But I can't do that because there is a heat pipe on my motherboard's capacitors that's in the way.
So - check that