Wait+Attack v Concentrate: does Shock actually not penalize 1-second spell rolls?

[Plane]

Picture a duel between some swordsman and a mage relying on spells which take 1 second to cast.

Unlike 3e as of 4e it appears to require taking a Wait to interrupt those per http://www.sjgames.com/gurps/faq/FAQ4-3.html#SS3.4.1.4

If you don't use a Wait, then your attack is always going to land before the mage begins casting.

That would have the benefit of inflicting shock (-1 to -4 to IQ rolls) against 1-second-casting spells per B419's "on your next turn only".

( I'm less certain how that works against 2-second spells you begin on the turn following an injury, since the IQ-based roll is not made in the 1st second (when shock is in effect) but rather in the 2nd second (when shock is not in effect). Do we have any answers on that? )

If however the swordsman Waits and then "Attack when the mage begins casting" since the mage has already begun their turn/maneuver, their "next turn" would be after the spell already finished casting, so no penalty to their skill roll from the shock?

Another issue besides the final skill roll for the spell is also the will roll made during "Distraction and Injury" on B236.

If shock applied during the turn in which you made that Will roll I would expect it to suffer the IQ penalty (since Will is a Secondary Characteristic derived from IQ) but since this Will roll is made immedaitely (not on the next turn) and shock only applies to the NEXT turn, would that make the roll unpenalized?

I used to think it would be penalized because I always assumed "shock is instant" and that it was "from the time you are injured until the end of your next turn", but it seems like maybe there's a grace period of "shock doesn't kick in until you begin a new maneuver" ?

I'm wondering if maybe this got amended at some later point, does anyone know?

B236 for example mentions this:

If you are injured but not stunned while concentrating, and succeed on
the roll to avoid distraction, you may cast your spell.
However, the shock penalty for your injury reduces your effective skill

So it sounds like shock doesn't penalized your Will-3 roll when injured, but it will penalize your spellcasting regardless of when you actually finish the casting and make the roll?

Does this make spellcasting the sole instance where shock operates differently? It seems there's two ways in which it might compared to other abilities:

1) it doesn't matter if it takes 60 seconds after being injured to finish casting your spell at which point you roll IQ: the shock still penalizes it
2) it doesn't matter if you finish casting your spell on that turn before your "next turn" when shock normally begins applying the penalty

I'm thinking my memory of B236 guided my overall impressions of shock, even though by the letter this only seems to apply to spells but not other IQ rolls made same-turn or 2+ seconds later.

A third possible roll is also something to consider, for missile spells. In addition to a will-3 roll during casting and the IQ roll when casting is finished, B240 describes a 2nd possible will roll (no -3 this time) if injured while HOLDING...

I used to think "apply shock" but if there is a delay-til-next turn then wouldn't that be too late?

I guess this could apply if you were hit consecutive turns while holding a missile spell (the 1 HP injury you suffer that triggered the first Will-0 roll makes the 4 HP injury you suffer the following second trigger a Will-1 roll?)

I guess the "one-two" approach would also be a good one for interrupting casting. The ideal would be to make a high-damage attack of something like 4 HP (maximize shock penalty, but it won't apply right away) and then on your next turn make a low-damage attack (1 HP is all it takes) since the Will-3 roll will suffer the shock from the previous turn (roll Will-7) and not the current one?

In fact even if that 2nd low-damage attack doesn't hit, you might prompt a Will-7 roll anyway if the mage defends?