@PepperJo so glad your D had a successful quarter with Calculus!
Unless my son’s summer advisor was just plain wrong, everyone was expected at least to start in their placement, so any 152’s or higher wouldn’t have been able to register in 151. This is what he was told, at any rate. I’m sure people dropped down as the quarter went on and true difficulties emerged but it’s not like the old system where you could register at your placement or lower. Like your D, my son attended all the problem sessions and office hours regularly. He also really loved his instructor. It sounded like those who made use of the available resources did significantly better than those who didn’t (no surprise there). My son found 152 to be challenging but thoroughly enjoyable. And now he’s done with Core Math 
Those invited to honors should have placed higher than 151 to begin with. They can drop back if it doesn’t work, but it’s doubtful they would land in 151.