Why is DC editorial mandating that Batman be older than Superman?
With New52 you could say that aas they preserved Batman's history he is older but then so should GL be but again whatever replaced Superman's history must have taken time too and he is the first superhero. The mandate even reached as far as Smallville Season 11where Batman is not only older but active before Clark both as Superman and the Blur. Here Batman's history too could have been truncated to keep him younger.
And again wasn't DCnU's whole purpose to make everybody younger. Why is Batman immune to that?
Or is the real reason Batman is older than Superman because he is currently making more money in comics so they are attenuating every aspects of him. If he is older he has more authority than the real world original superhero in the fictional realms?