Okay, Pepsi. Let me explain myself in detail why Sakura moving on before 540 makes no sense IMO. Prepare yourself for incoming LAP.
I do agree with you on the LOI. Sakura was trying to let go of her feelings for Sasuke, maybe even convinced herself she was over him, but obviously Sai's speech, Sakura's confession, Naruto's instincts, and Sakura's own behavior later all heavily indicate she wasn't. The whole arc definitely did affect her perception of Sasuke and her feelings for him, making her see him more negatively than she ever did before.
Sakura moving on from Sasuke was gradual process, starting from the very moment he left. There was never a specific moment. Sakura's feelings become much more Team 7-based and then the Kage Summit Arc was the arc that made the veil of "loyal, caring comrade Sasuke-kun" slowly get pulled out of her eyes, damaging her romantic feelings for him further because her love was already starting to lessen. And then we have Sakura allowing Sasuke to die to protect Naruto. Sure, it was extremely painful for her, but she was still willing to do it for Naruto's safety. That loses further credibility to her still being deeply in love with him.
However, you might be over-simplifying this. Remember, this is the Narutoverse. Sakura still possibly holding on to romantic feelings for Sasuke on some level even after murder attempts is really not that hard to believe. They're damaged by the murder attempts, to the point whatever she feels for Sasuke on romance level is getting closer and closer to disappearing true, but that doesn't mean she still doesn't have them.
Sakura didn't just get over Sasuke in a day. Exactly right. It wouldn't make sense to be like a switch, but it doesn't make any sense for Sakura to just get over Sasuke a few weeks after either. Sakura was so attached to her image of Sasuke. Only recently did she see how much she changed. She can't just wake up even after the Summit Arc and say "Nope, don't love Sasuke anymore". It's illogical, but Naruto has unrealistic focus on bonds of anyway so what do you expect? If Sakura didn't at least think she still loves Sasuke, then 540 wouldn't have happened and 676/678 would not be set up the way it was. Kakashi's speech in 675 was from his perspective. That's how he sees Sakura's feelings, but Sakura has not ever indicated she's aware of it. In fact, she's indicated the opposite. We go back to 540 & 676 again.
To explain this ... Let's say you're a little girl who had a favorite mirror. You loved that mirror so much as kid and took care of it, loving how it looks and how it made you feel. Then you lose that mirror. You're upset and became desperate to find it so you keep searching for it. Through the years that mirror, still missing wherever it is, is slowly getting small cracks in it the longer it's gone as you get older and start caring more about less superficial things. But you still remember how that mirror made you feel, nostalgia, all it's memories so you cling to it.
Eventually, you find that mirror again. You see small cracks in it but ignore it and take it back. But then, you accidentally drop that mirror and the glass suddenly starts shattering in heavy bits, but there's still some glass left. You're upset, but you tell yourself it's still just as pretty and useful as you remember it so ignore that little voice and bring it home anyway.
When you go home, you notice more it's not not making you feel the same and eventually, after more pieces of glass fall from the mirror, you stop telling yourself it's still perfect; it's broken and useless. You're sad because it's something you cared about so much and lS your childhood so you can't entirely accept it, but a part of you realizes you need to outgrow it. And finally, just as the last few pieces start to fall out of the mirror, you don't care as much as you thought you would. You realize that you've spend all this time looking for that mirror, but in truth you no longer needed it and that it's time to let go of your past shallowness. Then you take the broken mirror and throw it in the trash, turning your attention to more mature things.
This is Sakura with her love for Sasuke throughout the series. She's the little girl and Sasuke is that mirror. The Kage Summit Arc didn't make her move on from Sasuke, It only gave her a powerful wake-up call. It's all childhood hopes and nostalgia. It's a very powerful emotion that is easy to cling to, even when by now you've outgrown it. Sakura doesn't love Sasuke that way anymore, but childhood nostalgia still blinds her.
Sakura hasn't thrown out that "mirror" yet. She's going through desperation of losing it (PoaL, Early Part 2), getting small cracks in that mirror without acknowledging it (Sai Arc, Kakuzu Arc, Pain Arc), heavy shattering of that mirror but still telling yourself it's still okay (Early Summit Arc), and then sad acknowledgment it's not the same and part of you wants to forget it but another part of you still can't accept it (Late Kage Summit Arc, War Arc). She's in that phase. Sakura's faces at Sasuke's behavior (540, 635, 676, 678) ooze resigned but painful disappointment, something she shouldn't feel if she thought she didn't love him. The part of Sakura making peace and realizing she doesn't love Sasuke is coming up soon with the recent chapters, but saying she already has is wishful thinking IMO. We need consistent proof. A resolution like that should on-panel and not forced like the confession.
I would love to believe Sakura knows she doesn't love Sasuke, but logically I just don't. It doesn't really matter to me whether Sakura still has feelings for Sasuke, unconsciously moved on, or just moved on consciously. As a Sakura fan I would prefer the last one, but as a NS fan it doesn't matter. Whatever she has for Naruto is still much stronger than what she feels for Sasuke so I'm not going to be sensitive or picky even if she does love both of them romantically and 675 is just misinterpreted. I'd be okay with either of the three options for most part but if I don't see it, I don't see it.
I apologize for this embarrassingly long LAP and my lame mirror metaphor, but ... as long as it got my point across. 
Edited by xxRomanceGirlxx, 08 July 2014 - 08:59 AM.
