Fast Forward/Rewind

Why are the fast forward and rewind functions for the DVR so imprecise?  Perhaps this is related to the Coutour 2 box response issue; perhaps not.  Either way, it is incredibly difficult to resume watching at the desired point in a program.  For example, when zipping through a commercial, it is pure luck whenever I manage to get the recording to resume at the desired point.  I'm constantly going back and forth to get to the right spot.  Prior to Cox, I've had other cable providers (RCN, Comcast) and both satellite services.  I've never had a significant problem with this issue before.  Seems unacceptable to me.