Err, right, I agree. I'm saying that without any math, "doing it wrong" isn't so obvious. I'm saying that the difference between wrong or right isn't a great deal. Put differently, I'm betting Sim-C will give us this answer without having to walk the first 6 seconds of combat manually. I don't consider it at all clear that starting with rupture's one extra pulse of energy is going to matter, especially when my method is more likely to save a combo point for a damaging finisher instead of a slice that will be refreshed for free (aka wasted). However, I'm not saying I'm right. I just figure we'll get that answer for free pretty soon like.
Another possibility is mutilate to five then rupture, then slice at your opportunity. If rupture was good enough (instead of venomous wounds being the star player), then we'd give that a lot more consideration.