Hello all I have just read in the new rule book in the restrictions for allied detachments on page 122 that it states "All units chosen must have a different Faction to any of the units in your primary detachment (or no faction)". Does this mean that army's are not able to ally with themselves.

Also on page 118 where it defines factions the second paragraph says "in the case of older publications, the faction of all the units described in a codex is the same as the codex's title. In the case is codex supplements, the faction of all the units described in that publication is the same as the codex it is a supplement of".

I know that in the supplement books it states that they can ally with there parent books. But what do we follow the new rule book or what is in the supplements.

What does everyone think