Board Thread:Theories and Speculation/@comment-30355627-20161218164138/@comment-4136079-20161221214924

Elveonora wrote: But it was only a hypothesis which is actually untrue, since combining chakras of Asura and Indra present in their respective reincarnates recreates Hagoromo's chakra and thus the Rinnegan.

So basically, this is evidence that: 1) It isn't necessary to max out Uchiha ocular power before the Rikudou chakra fusion takes place.

2) Asura unlocking Rinnegan would first cause the Sharingan, then a Mangekyou Sharingan to appear, before the Rinnegan (think Obito awakening Mangekyou from a 2-Tomoe Sharingan).