LOL, you are so wrong. What Itachi gave/copy to Sasuke was his own MS jutsus(and autokill Madara Amaterasu), that's why Sasuke is so good from the start with his MS, because he got all the jutsus, information and maybe experience in using them, from Itachi. Although him shaping the Amaterasu over Susanoo may have been exceeding Itachi's skills(or he didn't need to use it xD).
LOL2, when EMS is when your MS is replaced by your own brother's MS, then you could say that MS is an incomplete EMS... but more properly would be to say that EMS is another level to MS, or you would need to say that Sharingan is an incomplete MS as well.
I belive that your misunderstanding comes from this page:
Here ha talks about awakening the 2 powers inside each of the MS eyes. It's not about having MS in both, but being capable to use one power from one eye, that later allows to use Susasno when using both.