Besides admissions officers, I don't know if anyone can truly know why a particular application was accepted or not. As you say, statistically it seems that the numbers really are the true determining factor, and that the other stuff may just help someone who is "on the line." I certainly played up as much of my non-traditional background in my personal statement as I could, especially as my 10+ year-old GPA wasn't that stellar. I put in all kinds of stuff about my successful career and my kids; I figured it was no less dumb than any of the other standard criteria law schools seem to care about that have nothing to do with how well you'd actually do in law school, e.g. ethnicity, growing up poor, charity work, or unusual hobbies. Did it work? I have been accepted almost everywhere I've applied, but of course I have no idea if it helped.