I thought in a 3-Deep coverage each defender plays a third of the field. Which on my opponents defense seemed to work.
http://mfn2.myfootballnow.com/watch/3810#701295 http://mfn2.myfootballnow.com/watch/3810#701318 http://mfn2.myfootballnow.com/watch/3810#701321 http://mfn2.myfootballnow.com/watch/3810#701335 http://mfn2.myfootballnow.com/watch/3810#701377

Then when I call the play the two outside defenders seem to each play half the field, and the other plays the center. Which may not sound very different, but in action has very different results.
http://mfn2.myfootballnow.com/watch/3810#701390 http://mfn2.myfootballnow.com/watch/3810#701338 http://mfn2.myfootballnow.com/watch/3810#701259