I don't think they ever did on the ipad. It's almost always been on computers and warranties etc.
I definetely remember they did, because I tried to convince my mom to use it when she got hers but she didn't. It was only $50 off for the normal iPad, but still, that's $50 that could be yours.
Never within 90 days of launch. They'll do EPP and EDU discounts after January 1 (Per Apple Customer Relations)
I used my EPP to get a discount on the 4th gen iPad w/ LTE. Not much mind you, but it was available.
The deal I'm talking about is the way it is on macs right now: Where you compare the store to the education store and it has a lower price. It was only $50 lower.