Power from Pain Black Heart Question

[Inquisitor Red]

I'm running two batallions: one a Kabal of the Black Heart, and the other a Wych Cult. Does the Black Heart Obsession trait of increasing the Power from Pain ability by +1 also effect the Wych Cult, or only the units in the Kabal of the Black Heart? I figured it only affects the Kabal based on wording but I just wanted to make sure.

[Slasher956]

Sub faction rules only apply to units of the sub-faction who are within a formation entirely of units of that subfaction (or with individual units that dont brake the kabal / wych cult)

 

ie if you took a 3rd formation that had units of both the Black Heart and the wych cult then none of those units would benefit from their obsessions how ever all the units in both mono kabal/cult formations would

 

 

pg 114 of the codex