Wow that is great. Extending distance for me has been a problem. One thing I noticed in your post is your rest time, which is a lot longer than mine. I am too much in a hurry to start the next set and I think that is also one of my problems. I do find that nasal breathing rather than bobs are much more helpful for me, but getting adequate rest time is important.
Looking fwd to your future post when you hit that magic mile!!