It goes the other way. See, while he was being abused for two hours a day that no one else experienced, he was experiencing 26 hour days when everyone else was experiencing 24 hour days. So his body adjusted to that.
I'm having a little trouble making the timeline work out on this, since one wouldn't be able to notice his sleep issues while the time-turner abusing was ongoing; it would be a consequence that appeared after the fact. It's mentioned in chapter 2 that Harry was in school when he was seven; that could be argued as evidence that his sleep issues hadn't quite manifested at that point, and that he'd been pulled out of school soon after, once they did.
But that still leaves a period of three or four years for Harry to readjust to 24 hour days. You'd think Harry and his parents would have at least tried some kind of therapy, if the issue was severe enough to pull him out of school, and in the absence of some kind of reinforcing factor, why wouldn't said therapy at least have made some progress on the issue?
The story clearly states Harry's explicit interest in not attending school, so he wouldn't have tried anything to change his sleep pattern for that purpose, and I doubt by the age of 10 he'd found any other important reasons to motivate sleep pattern changing therapy.
I also doubt his parents' preferences matter, here, and even if they did prefer he change his habits, I doubt they'd press him into therapy without his explicit, cooperative, interest.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 88-89. The previous thread has passed 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: