I would be surprised if it wasn't 50% off; if you are math savvy (and I am sure the math wizards at SE HQ figured this out) they can make more money with half off subs having 90%-100% of the current player base paying for the game then they would if they didn't give a discount and have 60%-70% of the current player base paying.

There are not stupid, a little slow, but not stupid
Luv u S-E~