I believe someone posted a while back (and it made perfect sense) that nobody was actually held back for an entire year.

The whole class simply had to retake the finals again.

So I think they were all held back for a couple of weeks (assuming there was a delay between re-takes).





As for the other argument going on in this thread, I'm not going to take sides here, bu I think that rootyb makes a good point.

Nobody is actually wrong, but there is a big misunderstanding here.

Some people are drawing on information in the anime/manga for their argument, and that's perfectly valid. The other side is talking about the real world, and using real-world logic to explain why the writer did things the way he did. This is also perfectly valid.

The problem arises when each side tries to argue that their side is right, while the other side is wrong. Neither side is wrong, it's just that you can't apply real-world logic to an anime series and expect to have no glitches.