Anytime the tire is making a track, the tracks are going to be easier on the machine.  The only time the tires will be easier on the machine is when you are on hard ground.  As you said, if the tracks are making a track, the tires are stuck.  Honestly we have very seldom made tracks with the tracks on.  The rear tires (23.1-26) on my machine will make tracks, but very seldom will the tracks.  Mike's machine with the 67-34-25's on the back just pretty well does not make tracks, period.  The cutterbar sinks in the mud before the tracks are cutting in more then an inch or two.  If the tracks are cutting in, you best make sure you have your mud boots laced tight before you step off the step.