Bob, I know what you're talking about... I've never made a lure with an intentionally canted bill though, in fear of messing it up and wasting time, but I have noticed it in some Bagley's. These slightly flawed lures sometimes outperform the "perfect" ones. They might possibly have a snappier action, yet I've never really taken notice.
Maybe the off angle allows the water to favor one side slightly more, causing it to swing out greater on that oscillation and less on the other, and thus you may observe an overall increase in movement. but idk... quick simple/naive thought