For the last 10 years that I've been a member of the program, points stays always counted toward nights, and you always got credits that were per night/stay.

Up until about 5 years ago (I can't remember exactly) you didn't earn any points on incidental spend during a points stay, but now you do.

So, with the current promotion, if your 30th night of the year were a points stay on a Sunday night, it cost 30k points, and you were a Diamond in a DoubleTree with no incidental spend, you'd get

1k points - per stay for the brand
2k points - for checking out
10k points - milestone bonus