iMac goes to Deep Sleep over night. Why?

I'll try to contact the authorised service provider. I don't think it's the hard drive sleep, I always used this feature and it has never been a problem.

I've just found out what is it. This is from: http://support.apple.com/kb/HT1757

"With the release of the OS X Mountain Lion v10.8.2 supplemental update 2.0, a new feature was introduced to enter safe sleep after four hours of the computer being connected to AC power. This is an effort to comply with the European Energy Standards (ErP Lot6). This will only occur if there is no wireless or Ethernet activity and no activity from external devices such as USB storage devices."

autopoweroff, standby, autopoweroffdelay nor standbydelay didn't make a difference for me, the computer always goes to Safe Sleep over night. I'm kinda frustrated form it cause whatever I try it's always the same. It sad that some of these settings (like autopoweroff) are not even described in man pages. :/

Furthermore they say "standby only works if hibernation is turned on to hibernatemode 3 or 25." and "standby causes kernel power management to automatically hibernate a machine after it has slept for a specified time period." So how come that my iMac hibernates when I have hibernate mode set to 0 and the "specified time period" is set to 24 hours???