Hehehe, this was so funny.
Here's to remind everyone that there is a big difference between Ayako/Asuka and these two!
Y'see, Asuka is a high schooler and nearly a grown-up. In one or two years she will be in college. She's way closer to being an adult than Yuuki.
A mother doesn't treat her daughter in middle school the same way she treats her daughter in high school. There's a huge difference. A middle schooler is closer to a child than to an adult. (Well, actually, that's not always true... but mothers will assume it is true, and act accordingly!)
It makes perfect sense that, while Yuuki is trying to be all suave 'n sexy to seduce Sayaka, Sayaka is like: "Never mind that shit. Have your grades improved!? What do you mean, no!?!? GO STUDY!!!"*