You have to log into the site to get the ruling, but you can find it under this thread.

@Dalmatio69 - Sorry for the brevity, but I hit submit too soon. You are correct that the bonus is not a modifier, but neither is it part of the attack value. The attack value itself is all that gets borrowed. The thread's title is 'Sorcery Rules questions', and it's on the Wizkids MK: Rules forum.

@yojimbo - I'm sorry about that part, too, but Sigma clarified that the faction requirement for spells must be met during army construction. I'm hoping they will release a rules update to that effect soon (as well as a real Apocalypse spellcaster...)

Should be noted for all the APOC heads that sharing the attack value works better for Kem. His second and third clicks are where the fun really starts, but his attack his a small 8. Those enforcers give him a 9 to play with, so long as you keep one back and healthy.

And then it's only a matter of time before the APOC gets a caster with a printed attack of 13.
THAT would be nasty.