If you have two monitoring software applications installed or open at the same time you can get huge differences. One application only is the rule of thumb.

My friend had the exact same issue (with other temp. numbers I believe) when he installed h110. When I visited him it turned out that he connected water pump to cpu_fan and one of two fans to cpu_opt. The other fan was connected to cha_fan. We changed it so fans were connected to cpu_fan and cpu_opt and water pump to cha_fan slot (you can connect it to any other slot). It actually eliminated this error. So, if it's not software related issue I recommend you to check if 3 pin water pump connector and 4 pin fan connector are not connected the same way as I mentioned before (since cpu_fan and cpu_opt on friend's motherboard are controlled by one fan speed profile in bios). I can actually be wrong thinking that fan speed profile can cause this, but it worked.