My experience is that the check-out date (or maybe confirmation numbers) is all that matters. For reservations with different weekday check-out dates (and by necessity. different confirmation numbers), I generally receive nights and points for all of my rooms. By contrast, a single reservation with multiple rooms (and by necessity, the same dates) generally receives night credit for one room and points for all rooms. My suspicion is that whoever reconciles the points and nights each weekday isn't necessary looking for overlapping reservations with different confirmation numbers.