If you think about it. Hermione was given a time turner in POA. Now, this has issues in itself which I've discussed in the POA thread, but it basically means that she was the only person from Gryffindore doing those subjects, but moving right along..... in short, there wasn't enough time for her to be taking all of those lessons. So she was given more.
But from COS, we know that Percy received 12 OWLs. Which is more than Hermione's and that he must have been taking every known subject offered- Charms, Potions, DADA, Herbology, History of Magic, Astronomy, Arithmancy, Care of Magical Creatures, Muggle Studies, Divination, Ancient Runes and Transfiguration (at least unless I missed out one, then he was taking almost all).
So how come Hermione can't fit all of those into a weekly timetable, but Percy can? It doesn't make sense that they would change it so that there were less opportunities for people to do all subjects, because those that WEREN'T would have an awful lot of spares. So maybe Percy had a timeturner. The responsibility that he would have shown with it would have definatly made him a Head Boy candiate.
Maybe that's how he had time to do all of his subjects, his prefect duties and date Penelope
Any thoughts?