When do Deathwing Knights activate their smite mode?

[Cactus]

Deathwing Knights may activate the smite mode of their Maces of Absolution once per game. The precise text is "One use only" under the special rules for smite mode with a footnote saying "All models in the unit must use their Mace of Absolution's smite setting at the same time."

Page 51 tells us that "Some weapons can be used in different ways, representing different power settings or types of ammo... Where this is the case, there will be a separate line in the weapon's profile for each, and you can choose which to use each turn."

Do I declare this...

1. ...at the start of the assault phase?
2. ...at some point during the charge sub-phase?
3. ...at the start of the fight sub-phase? If so, before or after challenges are made?
4. ...at the start of the initiative step the Knights fight at?
5. ...after rolling to hit but before rolling to wound?
6. ...one of the above, chosen by the player whose turn it is?

"One use only" is not a listed special rule so there's no help there. I'm fairly sure there's no RAW answer for this* but are there similar rules we can look to for guidance? Are there any ramifications of these possible answers that make any of them more or less credible?

I don't think it's controversial to say that in the case of shooting a combi-weapon you would declare which mode when you declare your target, immediately before rolling to hit. This leads me to think either 3 or 4 is the intention but I'd be interested to hear any other ideas.

PS. I think it's clear the correct definition of the noun "use" in this case is number 13 here, "an instance or way of employing or using something", so let's not go down that road please.

PPS. Let's also assume that "one" means 'one fight sub-phase' rather than 'one attack' or 'one game'.

*Now I expect to be proved wrong by the first reply!

[Fibonacci]

Combi-weapons are also normal weapons with a one shot mode.  I thought for sure there would be something in the BRB under combi-weaons that said you declare you are using the extra profile before rolling to hit .... but it ain't there!

 

Sweet.  I'm going to wait until I see if it hits before using my combi-meltas now ... (No, I'm not really going to do that.  I may be a jerk but not that much of one)

 

By convention we say we are using the special mode right before we roll to hit.  When a model has two or more melee weapons "he must choose which one to attack with when he comes to strike blows." (pg 51)  In the case of the Deathwing Knights I would say any time in the fight sub-phase up to their Initiative step but before rolling to hit.

[DarkGuard]

I think Fibonacci has the right of it here. That is the fairest and easiest way to rule it. Having it done before the Charge for example would be incredibly unfair should the charge fail. The Knights have a choice to use it once, and so treat it as a choice of weapons which when chosen, can no longer be chosen.

[Spinsanity]

I'd probably refer - even for the combi-weapon example given before - to the 'More than one weapon' rule on page 51 of the BRB.

You chose which one to shoot (not which one has shot) and chose which weapon to use in close combat when he comes to strike blows, which would mean you get to chose once the DWK initiative step comes up.

 

So I vote for option 4.

[Cactus]

Thanks for your replies. Number 4 it is then.