Antec TruePower's use a technology that slow down your fans (the power supply ones and any connected with the "Fan Only" connectors) when not needed in order to maintain quiet operation. When the system heats up, the fans speed up. Sooo, something monitoring the fans like PC Probe think there's a problem if the fans are spinning slower than usual because it doesn't know about the PSU regulating them. It's not a problem as long as your temperatures are staying in line. (I believe if you look in the Antec documentation, they make a statment about this too). So in summary, if your temperatures are okay, don't worry about it.
I'm new to this too (just got a TrueBlue 480 Watt from Antec), and while it is quieter than the Enermax I was using, my fans do run at much lower speeds and the system is warmer. (But it doesn't appear to be a problem so far - everything's staying cool enough). The idea I guess is just keeping the system cool enough and conserving noise pollution at the same time.
Hope this helps.