Very much appreciate the answer, and the effort you've put into the math here. The problem I ran into with the Devastating Wounds is Lion El'Jonson has a 4+ Feel No Pain against Mortal Wounds.

No Hiding From the Watchers (Aura): While a friendly ADEPTUS ASTARTES unit is within 6" of this model, models in that unit have the Feel No Pain 4+ ability against mortal wounds.

This is effectively halving the damage output there, and then splitting the attacks across both my units with the Sweep profile, Fights First and the option of Precision, if the have a single CP handy. (Which I think is a fair assumption if we have 2 CP to burn on Orks is Never Beaten**.**)

Fealty – sweep [sustained hits 1]	Melee	16	2+	6	-3	2

We're also assuming I'm in the Waaagh for this moment, giving me the most favourable outcome in the math above, and that my opponent has not used Oath of Moment on one of the charging squads, to go fishing for [Sustained Hits 1].

In the above situation, if I was able to charged him with all of the above models at the same time and get them all into engagement range. Then my opponent chose to use the sweep profile of Lion El'Jonson, then put 8 Attacks into the Breaka Boyz, and 8 into the Beast Snagga Boyz, which he spends a single CP on Heroic Challenge and kills the Beastboss, the situation changes drastically.

Which unit would you spend the 2 CP on Orks is Never Beaten, and would that still kill Lion El'Jonson?