Hmmm, I don't know! Am trying to get my head around what the difference is. I think the possible age range is still vast wherever they put the cut-off. I guess NSW are specifying the youngest age to start is 4.5, and the oldest is 6. Whereas if the cut-off was in line with school year the youngest would be 4 and perhaps they just think that's too young. Certainly I know Natalie is nowhere near ready to start school. It is only in the last couple of months that she has built the confidence to speak up in a group situation (like sharing news) and break into a peer-group play situation. I am pretty confident that she'd be able to locate her own bag and recognise her name (she can't spell/write it yet though), and she could open her own lunchbox but I seriously doubt she'd know what to eat at recess and what to save for lunch. I doubt she'd remember to put her lunchbox in her bag rather than just leave it in the playground. I doubt she'd be able to be responsible for her belongings and she'd ALWAYS want to take her shoes off as soon as she sits down, LOL. Just little things like that that would be helpful to be able to do when you start school.
Either that or the youngest you could start would be 5 and that would be too long to wait for some kids who are just socially ready earlier.
I'm still trying to get my head around it too...