Several of the changes I made after attending Rick Welch's class seem to diverge from the solid "bone to bone" allignment. He teaches shooting with a bent bow arm, and I shoot much more accurately that way. Of course, how much the bent bow arm contributes to that I couldn't exactly say, as he made about a half-dozen or so other changes to my shooting form at the same time. His double-anchor, for example, is a combination of thumb knuckle touching the bottom of the ear lobe (how less solid can you get than that?) and your nose against the back of the cock feather. Used correctly, his double anchor is practically free-floating, with just a tiny contact with your earlobe and your nose.
I can't tell you why these elements of form work better than other alternatives that might offer more "bone to bone" allignment; I can just tell you the fact that for me, they do.