Thank you for your response & it's helpful to know that but crikey that's a nuisance.

I'm trying to edit a listing by moving a book from the Non-Fiction - Other category to the Non-Fiction - New Zealand category. 

I wouldn't have thought there were different pricing structures within the books category. It seems hard to fathom that you can't move from Non-Fiction - Other to Non-Fiction - New Zealand or anything else within the book category? Surely that hasn't got anything to do with pricing structures? Is there a premium paperback category I'm unaware of?