NIS 2010 has built in defrag?

I'm looking through the help files for NIS 2010 and it appears the "optimization" task is actually a defragmentation program. 

 

I use PerfectDisk 2010 so I don't need (or want) Norton also trying to defragment my disk.  Even though the help "?" next to the "idle optimzation" leads to a blank help page, I'm assuming if I disable "idle optimization" it will disable NIS 2010's defragmentation.  Is this correct?

 

Is that all "optimization" does?