Regarding the whole Ami/Psycho Ami/Maya dynamic.
Maya is an unreliable source -- I'm not saying she's lying, but that she's already shown to have not interpreted the data she had properly, which has led to a number of wrong conclusions so far.
She may have seen Psycho Ami, but that doesn't mean she saw Ami go psycho. It could have been one of the angels piloting Ami, a shapeshifter posing as Ami (presumably, the existence of Himawarii implies that there might be others), or one of the other versions of Ami floating around (Bound Nao, broken Ami, etc). Not armed with the knowledge that the other potential Ami's or angelic abilities exist, she put 2 and 2 together and didn't realize that she got 22, not 4.