Sigh... no...
First I realize that all or nothing isn't the only way to go. Look at the Drazi attack run, also an issue for the same reasons.
As to the early vs late shot thing...
I suggested going back and finding the discussion on slow loading but let me sum it up. If I get to fire my weapon first at full AD, this is much more powerful than the same weapon with half the AD each turn.
Why, because on turns one and three I have achieved a much greater density of fire, and you tend to stay about half the AD ahead, unless the game goes to full turn limit. At least in our experience, most don't.
Getting your dice in first as opposed to spread over two turns means you have a much higher average chance of killing a sink before it gets to affect movement, before it gets to fire, etc. It has nothing to do with getting lucky, it has to do with early damage being stronger than late.
The single die aspect is the toss for getting to do the SA at all. If I pull it off I push myself that much farther ahead based on the single drop of A die. Like stealth, if I don't make my stealth checks early I tend to drop behind enough that making a bunch later no longer matters. Similar thing can happen here... make the rolls early and I become tough, miss a few early and it may not matter that I make a few later.
Ripple