If you're comfortable running that low without treating, and if you've been doing it long enough to make it work, then more power to you. And if you're dipping below 60 only a couple times a week, then I think you're doing fine. My fear, though, is this could be a symptom of something you discussed in one of your threads here (deferring treatment even when needed): Taking lows more seriously
I'm not suggesting an all-out break-out-the-glocose attack on a BG in the 70's or even the high 60's - I find I can treat that with a small piece of fruit or a few raisins. But I would treat it then, and not watch it fall any lower.
I've never heard any doctor say low BG shouldn't be treated until we're below 60. I'm curious where you've seen that?