Power supplies are manufactured with expensive wave-solder machines for a reason, consistency and quality and therefore hand soldering should be avoided when possible as it can mean inconsistency and potential long term reliability via over heating of pcb or components, cold solder and or solder...
I got the information from a distributor of CoolerMaster here in Europe. I was only curious to the validity of the information because he said it was serious. No biggie. As long as my 850 doesn't blow up, all okay for me.