It's possibly the case:
It's kinda hard to tell since the other panels don't continue this specific dialogue, and MJ's expression is looking neutral, of course, MJ being sassy like she is, she could be just messing with Peter, on the other hand, under Slott she can be a bitch, so maybe it's the arrogant one, or something else I didn't consider.
If that's the case then it's just poor writting and poor planning, Slott didn't have to do anything with MJ and Peter's relationship to "hide" that Spencer was gonna use her, she wasn't in ASM for a while and last time she had showed up she was being a bitch to Peter and was talking about how glad she is that she's not part of his life anymore, and then he makes her return in ASM#796 with her saying that she kinda misses Spidey, then #797 has her making out with him and then she rejects him because... He's Spider-Man, dumping in the the trash bin what she had said in the previous issue, and changing nothing of how he left Peter's and MJ's relationship from the last time he used them, except that maybe MJ is slightly less of a bitch, and somehow that's supposed to lead up to Spencer making them be back together in a way that makes absolutely no sense since Peter had no reason at all to apologize to her?
If Slott didn't do that out of malice to Spencer, or fans, but instead as a way to help pave the way to Spencer's run, then, he did a pretty damn bad job at it since the whole thing read like a mean spirited joke, and if you remove the romantic sequence, again, leaves Peter and MJ in the same spot of "we can't get back together", and Spencer was even worse at it since the way they get back together goes against the problems Slott gave to the relationship.
In short, if your theory is correct, those two really need to learn how to plan better lol.
To be fair, something like that is expected, Slott is the same guy who made Peter be okay with the whole Superior shit simply because "He made Aunt May stop limping", yeah, that one good action compensates all the horrible things he did... Top tier understanding of an emotional character like Peter who got more pissed at less.