That is how people answer questions usually. Also, Noriko says "you disappeared once before then, too", which to me sounds like she's talking about the second disappearance, rather than about accidental encounter after said disappearance.
Still, I take your point about weekends and Thursday, it does create room for doubt - perhaps their last actual meeting was not the usual tutoring. It may be somewhat of a special day of a week, given the game begins on Thursday.
Yeah, "usually" doesn't mean
always. Meaning it's an assumption. That is without taking into account that Noriko was overwhelmed by her emotions when she said this. We also don't know the full story about the bus as it got redacted, so Sensei not seeing her then, is an assumption as well. (Albeit so is him seeing her.)
Sensei technically only disappeared on Noriko once (twice, if you consider the bus thing). They still saw each other after the accident, when he first "disappeared", as like she said he wasn't opposed to seeing her:
but he actually disappeared on her later on due to Maya presumably. That could be what she was referring to. Noriko did also say:
"find you again", after she mentioned the last time she saw him, implying she had been referring to a time she had found him.
Also this:
5 years ago was when Maya entered the picture, I suspect, or close enough. She and Noriko immediately started competing and bickering.
Doesn't really fit imo, since Noriko said Almost 5 (not actually 5):
and has implied that they were being tutored at least by 10:
Noriko is 16
so almost 5 years ago, she'd likely be around 12, maybe 11. Not to mention "been later" implies she's referring to after it already happened, not when it started.
There's also stuff like Noriko implying she was tutored since she was 6:
and that Maya showed up a short period of time afterwards:
seemingly immediately making things difficult for Noriko:
In other words, it seems like Maya was likely close to 7 or 8 when she started being tutored, and their "bullshit" started around 7 years ago give or take.
Overall: It doesn't really fit the presumed timeline. Of course, I could be wrong, as that could be intentional. It's been implied that not everything that we've been told or shown is true:
There's also likely more to the story with Maya and Noriko that simply hasn't been revealed yet.
I definitely don't think the Bus story is just filler though. It also easily explains why she said Thursday. I think there just being a special tutoring day on a school day for their last meeting is quite a stretch. Especially since Noriko claims:
Thursday could definitely be an important day though.