(just an OCD nit-pick: "aka" means "also known as". What you meant is "such as" or even just "like")
Anyway, software is notoriously unreliable for accuracy when reading PSU voltages. Your PSU is likely absolutely 100% fine because it's a very high-end PSU and it's only 2 years old. It's still just a baby. Well, maybe it's a toddler by now, but you get the point. These PSUs are built to last 5+ years quite easily. The AX850 has a 7-year warranty! ;)
So, don't worry about it unless you're having performance or stability problems even at 100% stock. Even then, that doesn't mean it's the PSU.
Edited by TwoCables - 1/9/14 at 8:05am