So Just To Clarify

KS backers get Titans for free.

But where exactly do the cutoffs lie for the 66% discount?

You don't get a discount unless you had PA before titans was released.

But you can't buy PA since Titans was released. Wut?

Yeah that's the point

Even if it wasn't Early Access?

66% off if you bought the game before August 18th, 2015. No matter when you bought it during that time. Only requirement is before that date.