MS? In such a weird way?? Nah.. I think its something new.. I mean.. Both Itachi AND Sasuke's eye techniques.. Sasuke was able to match Itachi with his 'normal' sharingan.. (the genjutsu i mean) ...
I can almost guarantee you its only MS, If it was the PMS/EMS, then why did Madara offer him Itachi's eyes? If Madara can add another set of eyes to his collection to enhance his PMS/EMS, why offer it to Sasuke?
Sasuke will slowly start to become more blind and will later need either Itachi's eyes, or Madara's eyes.
And sorry buddy, I dont want to be rude, but Im not going to go in an argument with Itachi's vs Sasuke fight. Itachi was sick, busy dieing, he gave some of his power to Naruto, and he didnt fight with the intend to kill Sasuke, also, Sasuke have been caught so many times in Itachi's Genjitsu's I think that he will know how to counter it by now. Similar like how Guy knows how to counter Kakashi. So Its not really worth comparing Itachi with his MS against Sasuke with his Sharingan.
If you also look at a Mangaka's point of view, it would also make more sense to only make Sasuke have a MS, to spicy up the story, to force Sasuke to fight Madara some time, when he starts loosing his vision.
So sorry if I were rude, but seriously I have placed a lot of thought into it. And I can only think that Sasuke might have, what I would call AMS, which basicly is a S + MS and not a MS + MS to give you a PMS, So I would say at best it could have some of the powers of the PMS/EMS, like not having to go blind, but you dont have Immortal life, like when you have the PMS/EMS, but I highly doubt that, aswell as the fact that Madara offered Itachis eyes, to give him PMS. So that basically flaws this theory.